Danny reminded me that I still hadn’t read Empires of the Word: A Language History of the World. Since I know him a bit (at least internet “know”) I’ve decided I can’t put it off any longer, and I’ll tackle it soon. I just finished two books, Replenishing the Earth: The Settler Revolution and the Rise of the Angloworld, 1783-1939 and The Secret History of the Mongol Queens: How the Daughters of Genghis Khan Rescued His Empire. I can recommend the first, but not the second. Since I will (or plan to) review Replenishing the Earth, I won’t say more about it here. The Secret History of the Mongol Queens was written by the author of Genghis Khan and the Making of the Modern World. The author is a bit on the pro-Mongol side (he always ends up making Genghis Khan a benevolent warlord!), and his writing style doesn’t have the density which I prefer in these sorts of works, but Genghis Khan and the Making of the Modern World was a serviceable book. The Secret History of the Mongol Queens on the other hand is too sensational, and it seems rather obvious that the source material was much thinner than for Genghis Khan and the Making of the Modern World (he admits as much repeatedly), so he had to include a lot of apocryphal material, with caveats, to fill it out. I much preferred The Cambridge History of Inner Asia: The Chinggisid Age, which I read earlier this summer. A naturally more turgid work without a central narrative (each chapter was written by a different academic), but lots of dense data.

So what are you reading? What would you recommend? Over the years I’ve noticed I don’t read much science in book form; I much prefer papers. But since I don’t read physics or chemistry papers that means I haven’t recharged my familiarity, at least on a superficial level, with these fields in years. So I plan to a hit a few popular physics books at some point summer. And I’m always up for economics, world history, international affairs, cognitive psychology, etc.* I suspect I’ll avoid fiction until George R. R. Martin gets his next book out, but that might mean I’ll avoid fiction for a long time.

* In my short-term stack The Sea Kingdoms: The Story of Celtic Britain and Ireland, Lives of Confucius: Civilization’s Greatest Sage Through the Ages, Superfusion: How China and America Became One Economy and Why the World’s Prosperity Depends on It and The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us. In my medium-term “must-read” queue, How Pleasure Works: The New Science of Why We Like What We Like and Shall the Religious Inherit the Earth?: Demography and Politics in the Twenty-First Century.

I was a big Green Lantern fan when I was a kid. It may have been my favorite comic book, and I used to sneak into my brother’s room and read every issue he got.

I’m a grownup now, more or less, but sometimes those comic book heroes still get to me. At Comic Con last week, this wonderful thing happened when a young lad asked Ryan Reynolds — who will play Hal Jordan in the upcoming movie – about the Green Lantern oath:

I still know that oath by memory. And you know what? In general, it’s a pretty good motto for life, too.

If anyone saw an RSS notification for a post about science writers that doesn’t seem to exist, it’s because I published it by mistake before it was ready. I’ve now deleted it. Currently, the plan is to get it up on Thursday.

Cheers,

Ed

Every time governments fail to take serious steps on climate change, it seems the parlor game of predicting what our warmer world will look like heats up. And the newest of those predictions, appearing this week in the Proceedings of the National Academy of Sciences, pokes at what is presently one of the country’s most sensitive spots: immigration.

Michael Oppenheimer of Princeton published a study that estimates that between 1.4 and 6.7 million people could become climate refugees emigrating from rural Mexico to the United States between now and 2080. That’s 2 to 10 percent of the present Mexican population, and it doesn’t include people who would make the move for other reasons.

Is it a major concern? Yes. How much stock should you put in those statistics? Not much.

Oppenheimer and colleagues used projections of decreased agricultural output driven by rising temperatures to get these figures.

In the worst-case scenario would occur if temperatures were to rise by one to three degrees Celsius (1.8 to 5.4 degrees Fahrenheit) by 2080, if farming methods had not been adapted to cope with global warming and if higher levels of atmospheric carbon dioxide had not spurred plant growth. This would mean crop yields in Mexico would fall by 39 to 48 percent, the study said [AFP].

Other scientists agreed that a warming Earth could spur more migration, but questioned whether it is truly possible to disentangle climate change from other forces and pin statistics just on that.

The social consequences of global warming are always the hardest things to predict. Immigration rates are never driven by physics alone, but depend on plenty of other factors, such as U.S. border policies or the changing structure of Mexico’s economy. And it’s always difficult to tie specific social trends to climate change. People in rural areas have been migrating for a long time, whether to seek out work or because the rainfall’s dried up or the soil’s eroded [The New Republic].

In addition, the Arizona Daily Star reports that the fertility rate in Mexico has trended downward for decades. Its continued drop could cut into any migration increase tied to climate change. Douglas Massey, another Princeton professor, told the Los Angeles Times that even if agricultural production worsens, Mexicans aren’t going to come in a mass exodus in the U.S. unless there are lots of jobs here to be had.

Oppenheimer himself free acknowledges the fudgy nature of predicting climate change’s effects, and that while the numbers make for a sexy headline, you shouldn’t take them too seriously. He says:

“Our intention was to show that this problem is a substantial one. Our goal was not to project specific outcomes 80 years from now but to show the magnitude of problems that policymakers ought to pay more attention to. I don’t want to say that this will be the single biggest factor driving immigration, but it could become among the largest factors” [Arizona Daily Star].

Related Content:
80beats: Senators Cut Climate Change Rules and Renewables from Energy Bill
80beats: The New Murder-Mystery Game: Who Killed Copenhagen?
DISCOVER: It’s Getting Hot in Here: The Big Battle Over Climate Science, interviews with Judith Curry & Michael Mann
DISCOVER: The State of the Climate—And of Climate Science

Image: flickr / wonderlane

Look closely: This hairy, pulsating carpet is actually a group of harvestmen, an arachnid commonly known as daddy longlegs.

This aggregation of harvestmen helps fend off potential predators. When one of the arachnids senses danger, he moves his body up and down to create a vibration; a whole jiggling group of daddy longlegs provides an even greater deterrent. There’s nothing quite like teamwork to make your skin crawl. Via Boingboing:

Related content:
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Discoblog: Egad! Oldest Spider Web Dates Back to Dinosaur Era
Discoblog: Beetle-Inspired Adhesive Lifts Lego Man; Could One Day Do Same for Regular Man

One of the main criticisms of the population genetic pillar of the modern evolutionary synthesis was that too often it was a game of “beanbag genetics”. In other words population geneticists treated genes as discrete independent individual elements within a static sea. R.A. Fisher and his acolytes believed that the average effect of fluctuations of genetic background canceled out as there was no systematic bias, and could be ignored in the analysis of long term evolutionary change. Classical population genetics focused on genetic variation as abstract elementary algebras of the arc of particular alleles (or several alleles). So the whole system was constructed from a few spare atomic elements in a classic bottom-up fashion, clean inference by clean inference. Naturally this sort of abstraction did not sit well with many biologists, who were trained in the field or in the laboratory. By and large the conflict was between the theoretical evolutionists, such as R. A. Fisher and J. B. S. Haldane, and the experimental and observational biologists, such as Theodosius Dobzhansky and Ernst Mayr (see Sewall Wright and Evolutionary Biology for a record of the life and ideas of a man who arguably navigated between these two extremes in 20th century evolution because of his eclectic training). With the discovery that DNA was the specific substrate through which Mendelian genetics and evolutionary biology unfolded physically from generation to generation a third set of players, the molecular biologists, entered the fray.

The details of genetics, the abstract models of theorists, the messy instrumentalism of the naturalists, and the physical focus of the molecular researchers, all matter. Through the conflicts between geneticists, some arising from genuine deep substantive disagreement, and some from different methodological foci, the discipline can enrich our understanding of biological phenomena in all its dimensions. Genomics, which canvasses the broad swaths of the substrate of inheritance, DNA, is obviously of particular fascination to me, but we can also still learn something from old fashioned genetics which narrows in on a few genes and their particular dynamics.

A new paper in PLoS Biology, Cryptic Variation between Species and the Basis of Hybrid Performance, uses several different perspectives to explore the outcomes of crossing different species, in particular the impact on morphological and gene expression variation. You’ve likely heard of hybrid vigor, but too often in our society such terms are almost like black-boxes which magically describe processes which are beyond our comprehension (hybrid vigor and inbreeding depression freely move between scientific and folk genetic domains). This paper attempts to take a stab at peeling pack the veil and gaining a more fundamental understanding of the phenomenon. First, the author summary:

A major conundrum in biology is why hybrids between species display two opposing features. On the one hand, hybrids are often more vigorous or productive than their parents, a phenomenon called hybrid vigor or hybrid superiority. On the other hand they often show reduced vigour and fertility, known as hybrid inferiority. Various theories have been proposed to account for these two aspects of hybrid performance, yet we still lack a coherent account of how these conflicting characteristics arise. To address this issue, we looked at the role that variation in gene expression between parental species may play. By measuring this variation and its effect on phenotype, we show that expression for specific genes may be free to vary during evolution within particular bounds. Although such variation may have little phenotypic effect when each locus is considered individually, the collective effect of variation across multiple genes may become highly significant. Using arguments from theoretical population genetics we show how these effects might lead to both hybrid superiority and inferiority, providing fresh insights into the age-old problem of hybrid performance.

There are various ways one presumes that hybrid vigor could emerge. One the one hand the parental lines may be a bit too inbred and therefore have a heavier than ideal load of deleterious alleles which express recessively. Since two lineages will likely have different deleterious alleles, crossing them will result in immediate complementation and masking of the deleterious alleles in heterozygote state. Another model is that two different alleles when combined in heterozygote state have a synergistic fitness effect. We generally know of heterozygote advantage in cases where there’s balancing selection, so that one of the homozygotes is actually far less fit than the other, but the fitness of the heterozygote is superior to both homozygotes. But that is not a necessity, and presumably there could be cases where both homozygotes are of equal fitness, but the heterozygote is of marginally greater fitness.

As for hybrid inferiority, a simple model for that is that lineages have co-adapted complexes of genes which are enmeshed in gene-gene networks. These networks are finely tuned by evolution and introduction of novel alleles from alien lineages may lead in destabilization of the sensitive web of interconnections. This model taken to an extreme is a scenario whereby speciation could occur if two lineages become mutually exclusive on a particular genetic complex which is “mission critical” to biological machinery (imagine that the gene involved in spermatogenesis is effected).

These stories are fine as it goes, but they do have something of an excessively ad hoc aspect. A little light on formalization and heavy on exposition. In this paper the authors aim to fix that problem. To explore genetic interactions in hybrids, and how they effect gene expression, they selected the genus Antirrhinum as their model. These are also known as “snapdragons.” Like many plants Antirrhinum species can hybridize rather easily across species barriers. They observe the effect of taking genes from a set of species and placing them in the genetic background of another. In particular they are focusing on A. majus, hybridizing it with a variety of other Antirrhinum species, as well as introgressing alleles from the other species onto a A. majus genetic background (so an allele on a specific gene is placed within the genome of A. majus).

Just as they focus on a specific genus of organism, so they also focus on a specific set of genes and the molecular and developmental genetic phenomenon associated with those genes. The genes are CYC and RAD, which are located near each other genomically, with CYC being a cis-acting regulator of RAD. In other words, CYC modulates the expression of RAD which is on the same chromosome. Variance in gene expression simply defines the concrete difference in levels of protein product. Mutant variants of CYC and RAD, cyc and rad, are created by insertion of transposons. Insertion of transposons can abolish gene expression, resulting in removal or alteration of function. What is that function? I’m rather weak on botanical morphology, so I’m going to be cursory on this particular issue lest a reader correct me strenuously for misapplication of terminology. So I’ll show you a figure:

I added the labels. C is basically what majus should look like, while G is a totally “ventralized” mutant. B and F approach wild type, but the other outcomes are more mixed. Note the genotypes in the small print. Table 1 measures the expression levels of the gene product for the various genotype:

Look at the first row; mutant variants of CYC which are nonfunctional reduce normal copies of RAD down to 20% levels of gene expression. That’s because CYC is a transcriptional regulator of RAD. The process is not reversed. RAD lacking functionality does not impact CYC (last row). Finally, the heterozygote states does result in reduced dosage of the gene product. Though the phenotypes might be closer to wild type than the mutant, the molecular expression of the gene is substantially changed. This is one of the issues which is always important to remember: the extent of dominance exhibited by a sequence of phenotypes consequent from a particular genotype may vary dependent on which phenotype you are a highlighting. On a molecular level there is incomplete dominance. Additive effects. On the level of exterior morphology there is more perceived dominance. This is not even addressing the issue of pleiotropy, where the same gene may have dominant and recessive expression on two different traits simultaneously in inverted directions (i.e., the recessively expressed allele in trait A may be dominant in B, and vice versa).

Figure 1 shows the different allelic expression levels in hybrids of Antirrhinum species. But what about the impact of the combinations on phenotype? I’ve reedited figure 4 so it fits better on this page:

Here’s the text description for the figure:

GEM spaces for CYC and RAD, showing location of various genotypes and species.

(A) Dorsalisation index for each position in GEM space using values from Table 1. Standard errors for DI_cor and expression levels are shown (if error bars are not visible, they are smaller than the symbols). A smooth surface has been fitted to the data (see Materials and Methods for details of surface fitting). Note that the wild-type, C, lies on a plateau while the double heterozygote, E, is on the slope. (B) Top view of the GEM space, incorporating the relative expression values from the species taken from Figure 1 (circles). These values were adjusted assuming that A. majus (red circle) is at position (1, 1) in gene expression space. Triangles indicate expected gene activity values in the double heterozygote (CYC = x×0.6; RAD = y×0.5; see Table 1E). Some of the double heterozygotes are predicted to have DI values above or below the position of A. majus. Triangles pointing upwards indicate species showing notch phenotype. (C) Enlargement of rectangle in (B). bra, A. braun-blanquetii; cha, A. charidemi; lat, A. latifolium; lin, A. linkianum; maj, A. majus; meo, A. meonanthum; pul, A. pulverulentum; str, A. striatum; tor, A. tortuosum; cha-BC, introgression of A. charidemi into A. majus background.

GEM = gene expression–morphology (GEM) space. As I note above the mapping between the manifestation of genetic variation on the molecular level and on the gross morphological level may be subtle. Figure 4 has the two genes under consideration forming a plane through the x and z-axes, while gross morphology is illustrated on y-axis. What’s on the y-axis is actually a principal component which serves as an abstract representation of the morphological variation of the petal structure illustrated in the earlier figure. They call it the “dorsalization index” (D_i). The wild type = 1 and the expressed mutant = 0. So the interval 0 to 1 in phenotype space is a good gauge as to the deviation of the morphology from wild type.

The letters in panel A are representations of the letters in the first and second figures within this post. G represents the double homozygote mutant. It stands to reason that its D_i is ~ 0. C, B, F, and to some extent E, form a “plateau” where gene expression may vary a fair amount but the morphology remains relatively stable. A, D, H and I represent intermediate cases on the “slope” where changes in genetic architecture produce large shifts in phenotype. The idea of dominance and recessiveness already indicate that not all genetic variation is created equal, and that there are non-linearities in the interaction of genetic variation and phenetic variation. Here using D_i and quantitative levels of gene expression one can take the verbal/qualitative insight and translate it into a quantitative relation.

Panel B seems to be similar to L. L. Cavalli-Sforza’s synthetic maps of PC variation of gene frequencies. It’s taking the y-axis in A and transforming it into the clinal grade on the plane. The circles in panel B represent conventional hybrids between A. majus and other species within its genus. There is variation in gene expression levels within these hybrids, but note that they reside on the phenotypic plateau. In contrast, the triangles show double heterozygotes: (CYC RAD)/(cyc cyc). The heterozygote combinations are for a variety of species, as indicated in the figure text. Note that they explore more of the phenotype type space, as evident in panel C, which is just an zoom of the rectangle in panel B.

So far they’ve shown that homozygote mutants abolish the wild type morphology, while heterozygotes of various combinations move over phenotype space. RAD’s expression is contingent on CYC, so that can explain some of the unpredictability of the variation when viewed in light of a simple qualitative model. Additionally, wild type hybrids move in the gene expression dimension, but not in the phenotype space. So next they looked at the impact of a particular species CYC and RAD genes against the majus genetic background in the doubly heterozygote state. In other words we’re not talking about a hybrid where half of the total genome content is from each parental species. We’re talking about introgression of alleles at a specific locus from species A to species B, so that the nature of the total genome content is of species B, except at a particular locus or set of loci, where they are from A. Figure 5 shows the results of such a cross:

The result of these studies show that alleles from A. charidemi are much more efficacious in maintaining wild type phenotype in the heterozygote state than A majus. This is because of underlying gene expression differences across species. Observe that CYC^char is particularly relevant because of the dependence on the RAD locus upon CYC in terms of gene regulation. The presence of charidemi and majus derived alleles on the same chromosome, so that cis--acting dynamics were operative, was achieved through recombination. A further exploration of the expression of each allele individually confirmed that CYC^char had a 30% higher expression than CYC^maj.

OK, so at this point we’ve examined the general topology of GEM. The relation between morphology and gene expression, the nature of the landscapes which describe their relationship. Next, we’ll move to GEF, gene expression–fitness (GEF) spaces. Genes/gene expression, phenotypes, and fitness, are the three-legged-stool of evolution, and specifically natural selection and adaptation. In a proximate sense the relationship between genes and phenotypes are physically mediated by a sequence of developmental pathways over life history. In an ultimate, evolutionary, sense, the relationship between genes and phenotypes are mediated by fitness, with variation in phenotypes over time being driven by variation in genotypes via the engine of fitness differentials. The distinction between evolutionary and non-evolutionary genetics, the abstract/theoretical and concrete/empirical, crops up with something like epistasis. On the one hand epistasis refers to physical relationships between genes. On the other hand it can also describe the variation in trait value which emerges from the interlocus interactions. And finally, it can refer to non-linear fitness effects due to combinations of alleles across loci.

In this case we’ve already seen how variation on the molecular level of gene expression due to genetic differences at two loci do not always translate into variation in morphology. The plateau in GEM space is simply due to the invariance in the morphological dimension. Once variance shows up you see the plane tilt and become steep. GEF space is exactly analogous, except that we are looking at variation in fitness on the y-axis. This is the domain of evolution, the ultimate. This section has only one figure:

GEM was based on concrete observation and experiment. GEF space is more theoretical, insofar as from what I can tell they didn’t measure fitness in actual lineages, but rather hypothesized distributions of fitness from parameters which might give us insight into hybrid vigor and/or breakdown. Red is obviously increased fitness and blue decreased. The surface of the landscape is simply where the gene expression values intersect with realized fitness. There are several alternative topologies here. I’ll quote the figure text:

Gene expression levels for two genes are plotted along the horizontal plane while fitness is along the vertical axis. (A) Radially symmetrical peak. (B) 2-D Projection of (A) showing location of effectively neutral zone and position of two parental genotypes (P1, P2 triangles), the resulting F1 (square) and additional genotypes observed in the F2 (diamonds). The F1 in this case is nearer to the centre of the peak while the F2s have similar fitness to the parents. (C) Diagonal ridge. (D) 2-D projection of diagonal ridge showing tilted elliptical neutral zone. The F1 is nearer to the peak than the parents but some F2 genotypes may now have lower fitness and fall outside the neutral zone. (E) Curved ridge. (F) 2-D projection of curved ridge showing banana-shaped neutral zone. Some F1 genotypes may have lower fitness and fall outside the neutral zone.

First, one has to introduce the concept of ‘drift load.’ A population of a particular genotype has an expected fitness, while in the best-of-all-world’s there is an idealized fitness peak. Random genetic drift will drive the population away from the peak because variance which shifts the gene frequencies from generation to generation. The power of drift to alter gene frequencies is inversely proportional to effective population size, N_e, the proportion of the population contributing to the genes of the next generation (often a rule of thumb is 1/3 of the census size, though this probably applies for human-scale organisms; usually it is much smaller than census). The drift load is the drag on fitness induced by drift, and is defined by the equation: ~1/(4N_e). In other words, as N ? ? the drift load disappears because sample variance is eliminated. But this load is applicable at each loci, so if you sum up across many genes then small increments can produce a non-trivial fitness decrement simply due to the vicissitudes of generation-to-generation variance.

In the figure above the dark red zone is neutral. That means there’s no fitness variance. That’s the “fitness plateau” equivalent to the phenotypic plateau observed above. P1 and P2 are parental generations, different lineages. F1 are hybrids, while F2 are crosses of the hybrid generation. The deviation of P1 and P2 in all the panels from the center of the fitness plateau are indications of drift load. The shape and nature of the fitness plateau are critical in determining the outcomes for the F1 and F2 generation, and consequent vigor or breakdown. Geometrically you see the rationale for hybrid vigor in panel A and B, as F1’s are closer to the center of the fitness plateau as drift load is dampened on the cross. In the text the authors note that ‘the variance around the optimum of the mean of two independent populations is half that of either one, and so the “drift load” is half as great.’ So instead of ~1/(4N_e), you have ~1/(8N_e). This is a gain in fitness which can be substantial over many loci. Over 1,000 genes it would be a gain of 0.125, which is very large, and can explain heterosis. But as many farmers know the F2 generation often exhibits a regress in fitness. “Hybrids do not breed true.” In a Mendelian model some of the offspring of the hybrids will segregate the alleles so that homozygotes will reappear. In panel A the F2 have about the same fitness as the parental cases. In panel B this is not the case; new genotypic combinations presumably are produced which lay outside of the fitness plateau, and this leads to a major hybrid breakdown. In panel C the F1 are slightly below the parental populations in fitness, while the F2 are far below them.

In the discussion they then work back from the theoretical digression to its relevance to observed variation, and their particular model taxon:

The phenotype and fitness of species hybrids will reflect the extent to which these various GEF scenarios apply to the many thousands of genes in the genome. Radial or elliptical neutral domains, centred around a common position in GEF space, would be expected for loci that are under similar normalising selection in multiple environments. This situation likely applies to the CYC and RAD genes as all species in the Antirrhinum group have similar asymmetric closed flowers. It would also be expected for many loci controlling basic physiology and growth. F1 hybrids would therefore be expected to show higher fitness and increased performance with respect to these traits. This provides an explanation for hybrid vigour that avoids the pitfalls of previous models that require fixation of loci with major deleterious effects or that invoke special mechanisms for heterozygote advantage. A similar explanation has been proposed to account for the origin of hybrid vigour between domesticated inbred lines…Hybrid vigour is usually lost in F2s or recombinant inbred lines, indicating that many of the loci involved interact to give tilted rather than untilted neutral zones.

Although hybrid vigour is commonly observed for physiological traits, the overall fitness of species hybrids is often lower than that of the parents, with sterility or other dysgenic effects being observed. This observation may partly reflect adaptation to different environments and thus shifts in the shape of fitness surfaces that drive changes in genotype. However, it may also reflect loci that interact to give curved or L-shaped neutral zones…Such zones will be prevalent for traits that involve more complicated epistatic interactions, perhaps accounting for the dysgenic effects observed in F1s. The negative contribution of loci with curved neutral zones is likely to increase with time, as loci drift towards the extremities of the banana-shaped neutral domains.

Remembering that there is a possible association between cis-elements and physiological traits,. it is interesting to observe that one may be able to infer fitness landscapes from patterns of morphological and genetic variation. I don’t know how robust the generalizations above are, and obviously this particular paper is more about setting up a testable framework than validating that framework, but we’ve come a long way from “beanbag genetics.”

Citation: Rosas U, Barton NH, Copsey L, Barbier de Reuille P, & Coen E (2010). Cryptic Variation between Species and the Basis of Hybrid Performance. PLoS biology, 8 (7) PMID: 20652019

Image Credit: Wikimedia

Lake Ontario has some key differences compared to her equally-sized sister lake, Ontario Lacus: The Great Lake has water; Ontario Lacus has methane, ethane, and propane. The Great Lake invites sunbathers; Lacus’ beaches, almost ten times further from the sun, are icy cold. The Great Lake is located on Earth; Lacus on Saturn’s largest moon, Titan. Despite all these distinctions, new research points to an important similarity: liquid levels in both lakes change with the seasons.

From June 2005 to July 2009, the Ontario Lacus shoreline has receded by about 6 miles, Alexander G. Hayes and his coauthors report in two papers submitted to Icarus and the Journal of Geophysical Research. Looking at other lakes in Titan’s southern hemisphere, it seems they are dropping in depth by about three feet per year.

Despite its shoreline’s rapid retreat, there is little worry that Ontario Lacus and other Titan lakes will disappear forever. Scientists expect that the evaporation is just part of a cycle of evaporation and condensation, that changes with the seasons. The four years of observation, carried out by NASA’s Cassini spacecraft, represents only the period from about mid-summer to fall, since a Titan year lasts 29.5 Earth years.

The discovery that Titan’s lakes are evaporating. . . suggests that there are active weather and geological cycles on Titan analogous to those on Earth. But on Titan the liquid driving those cycles is not water but methane, explained Oded Aharonson, a planetary scientist at the California Institute of Technology.“This is a wonderful opportunity and rare in the solar system to observe a planet with working liquid on its surface, a volatile agent that is responsible for altering its geology and participating in its weather cycle by evaporating and precipitating,” Dr. Aharonson said.[New York Times]

The Synthetic Aperture Radar (SAR) on the Cassinni spacecraft provided the data to help the researchers determine the lakes’ properties and see into their depths. Hayes explains:

“[The liquid] is fairly clear to radar energy—that is, transparent, like liquid natural gas.” Because of this, radar can see through the liquid in Titan’s lakes to a depth of several meters. “Then the radar hits the floor, and bounces back,” he says. “Or, if the lake is deeper than a few meters, the radar is completely absorbed, producing a ‘black’ signature.”[California Institute of Technology]

By watching how images created from this radar data (see image right) changed over four years, the researchers witnessed the evaporation in detail.

“Cassini continues to take our breath away as it fills in the details on the surfaces of these far-off moons,” said Linda Spilker, Cassini project scientist based at JPL.[NASA/JPL]

Given all that evaporated methane, a visit to the surface might have a similar effect.

The amount of methane gas produced by the changes seen so far exceeds the methane expelled by all the cows on Earth over a year, according to the press release. Yeah, might want to rethink that vacation after all. [DiscoveryNews]

Related content:
80beats: Weird Chemistry on Titan *Could* Be a Sign of Methane-Based Life
80beats: New Take on Titan Hints at More Fuel for Potential Life
80beats: New Evidence for Ice-Spewing Volcanoes on Saturn’s Moon Titan
80beats: Hydrocarbon Lake on Saturnian Moon May Be a Hotspot for Alien Life
80beats: On Saturn’s Moon Titan, It’s Raining Methane

Image: NASA & Cassini Radar Science Team, NASA/JPL/Caltech

Do you know an early career scientist who has demonstrated excellence in engaging the public on scientific topics? Go nominate her or him for the AAAS Early Career Award for Public Engagement with Science:

A monetary prize of $5,000, a commemorative plaque, complimentary registration to the AAAS Annual Meeting, and reimbursement for reasonable hotel and travel expenses to attend the AAAS Annual Meeting to receive the prize are given to the recipient.For the purposes of this award, public engagement activities are defined as the individual’s active participation in efforts to engage with the public on science- and technology-related issues and promote meaningful dialogue between science and society.

The award will be given at the AAAS Annual Meeting.

Details about eligibility and the submission process here.

Every three years the Librarian of Congress reviews the Digital Millennium Copyright Act (DMCA), and James H. Billington’s review just expanded digital freedom with this year’s ruling of new exemptions to the copyright law.

Jailbreak that iPhone

First and foremost, Billington ruled that it’s not against the law to jailbreak a phone (the practice of working around the device’s security system and taking more direct control of it). The Electronic Frontier Foundation lobbied hard for this, particularly with the iPhone in mind. Because Apple keeps tight reins on the device—offering only AT&T phone service and acting as gatekeeper for what apps can be added—many people had taken to jailbreaking the phone.

About 4 million iPhone and iPod Touch units had been jailbroken as of last August, and were accessing apps from a sort of black-market storefront called Cydia, the marketplace’s founder told Wired. The store is a haven for many developers that Apple, the gatekeeper to its App Store, has ignored or turned away [Los Angeles Times].

The ruling may be a victory for free use, but that doesn’t mean you should go out and jailbreak that iPhone straight away. Apple, which has staunchly opposed the legalization of jailbreaking, says it leaves the phone open to attacks and the user without access to software upgrades. Oh, and by the way, Steve Jobs and company will still void your warranty if you do it.

Circumventing copyright protection isn’t a crime—sometimes

Billington also ruled that breaking the copyright protection on DVDs is not, by itself, illegal. It’s what you do with it that matters.

College professors and students, documentary filmmakers, and those making noncommercial videos, are now able to circumvent the copyright protection on DVDs in order to use short clips from those DVDs in new works “for the purpose of criticism or comment” [PC World].

Simultaneously, a federal appeals court ruled much to the same effect in a case involving MGE UPS Inc., which makes backup power devices. The company sued after hackers figured out how to bypass a dongle system MGE developed, but the court dismissed the case saying that the act of hacking the system is not itself a violation of the law.

In other words, just circumventing the technology isn’t enough to get into trouble with the DMCA. The circumvention must lead to some violation of copyright [Ars Technica].

Video games and e-books

The rules on e-books have been updated, too. Many of them have restrictions on the read-aloud option, which book publishers wanted so that your e-book couldn’t double as an audio book. The Library of Congress made it legal to work around that restriction, but only if no audio book exists for that title (no matter what it costs).

And hacking video games is now OK, too, so long as you’re doing it for “good faith testing” of possible security problems.

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Bad Astronomy: Resolving the iPhone Resolution

Image: Apple

Particle physicists hunting for the Higgs boson reported their latest findings yesterday at the International Conference on High Energy Physics in Paris. The big two–Europe’s Large Hadron Collider and Fermilab’s Tevatron Collider (in Illinois)–gave updates, and other conference buzz included talk of a new facility, the International Linear Collider, which may one day give physicists a cleaner look at the other colliders’ results.

Large Hadron Collider — More Detailed Models Help the Search

Currently operating at 7 Tera electron Volts (TeV), the Large Hadron Collider is the world’s most powerful particle accelerator. Though electrical malfunctions hindered the collider in 2008, now LHC scientists report that they have made up for lost time: finding in months, what took the Tevatron, with its 2 TeV collisions, decades.

“The scientific community thought it would take one, maybe two years to get to this level, but it happened in three months,” said Guy Wormser, a top French physicist and chairman of the conference.[AFP]

As Symmetry (a Fermilab/SLAC publication) notes, these findings are more than a test of strength–or a simple retracing of the Tevatron’s footsteps. LHC physicists have to show that their facility can reproduce the results other machines have already seen, if one day they are to be sure that their data indicate something new.

As also reported by Symmetry, because the LHC is running at energies 3.5 times the Tevatron’s, these higher energies allow LHC physicists to refine their previous understandings, teasing out details impossible to see at lower energies. Such details may help physicists refine their search for the Higgs, the particle that presumably gives mass to all other particles.

CERN, the European umbrella organization that runs the LHC, says that these tests show the collider is ready for that search.

“Rediscovering our ‘old friends’ in the particle world shows that the LHC experiments are well prepared to enter new territory” said CERN’s Director-General Rolf Heuer. “It seems that the Standard Model is working as expected. Now it is down to nature to show us what is new.”[CERN]

Tevatron — Telling Physicists Where Not to Look

Meanwhile, Tevatron researchers have narrowed the expected mass of the missing particle. The diagram above shows the expected mass ranges, and those excluded by the new Tevatron data and previous Fermilab experiments. For reference, the proton has a mass of a little less than one GeV/c^2.

[P]hysicists’ standard model of the fundamental particle does not predict how much the Higgs itself will weigh. So scientists must go searching for it. Previous experiments show that it probably has a mass between 114 and 185 giga-electron volts (GeV), or 121 and 197 times the mass of the proton. Last year, experimenters working with D0 (aka DZero) and the Tevatron’s other particle detector, CDF [Collider Detector at Fermilab], took a chunk out of that possible range, reporting that the Higgs most likely does not weigh between 162 GeV and 166 GeV. Now, they’ve widened that “exclusion window” to between 158 GeV and 175 GeV.[Science Now]

Given such results, physicists have submitted a proposal to Fermilab asking that the Tevatron’s life be extended beyond 2011 to 2014, but the lab can’t guarantee that given its limited resources and other ongoing experiments and new projects.

Currently CERN officials have scheduled an LHC shutdown for 15 months also in 2011, which might give an operating Tevatron a chance to find the Higgs, Robert Roser of the Tevatron’s CDF detector told The Guardian.

“The LHC won’t be able to say anything about the Higgs particle until well into 2013. If we can run until 2014, we should be able to see the Higgs boson whatever mass it has,” said Roser. [The Guardian]

International Linear Collider — A Future, Cleaner Look?

Given results from the LHC and Fermilab, scientists continue to discuss new colliders, such as the International Linear Collider. Unlike the Tevatron and the LHC, which spin particles in a circle and then collide them, the International Linear Collider will force electrons and their antimatter-pair, positrons, to face off in a straight, approximately 20-mile long tube. Researchers say the collider would complement ongoing research at the LHC, by giving scientists a less powerful but cleaner look at the data, in part because the linear setup will ensure that particles that didn’t smash in the initial collision won’t continue circulating through the detector, Popular Science reports. They hope to start building the detector in 2012, but it will require international funding, the AP reports, amounting to $12.85 billion. Barry Barish, director of the proposed collider, told the AP:

“If we are going to build an ambitious machine, then it’s got to be a global machine.”[AP]

A video describing the ILC is available, here.

Related content:
80beats: LHC Sets a New Personal Record: 10,000 Particle Smash-Ups per Second
80beats: A Sweet Smashup: The LHC Shatters the Collison Energy Record
80beats: In 1 Week, the LHC Will Try to Earn the Title, “Big Bang Machine”
80beats: Rumors of the LHC’s Demise Have Been Greatly Exaggerated
80beats: LHC Beam Zooms Past 1 Trillion Electron Volts, Sets World Record

Images: CERN, Fermilab

Graphing variables is a critical skill in science. If something depends on something else — like the speed of sounds depends on air density, or the surface gravity of an object depends on its size — then if you plot the two things on a graph, you should see a pattern. The result is a line, or a curve. If the two things don’t depend on each other, you get a random collection of dots: a scatter plot.

About a hundred years ago, two astronomers plotted the brightness of stars against their color (from blue to red) and what they found was amazing: a clear connection between the two! In fact, stars fell into several groups, and over the years we’ve learned about why that happens. Most stars are stable, like the Sun, and fall into the Main Sequence of the plot. Some are old, some young, some dying, some dead. And they all have their place in what we now call the Hertzsprung-Russel diagram, or H-R diagram for short. It’s one of the most useful tools astronomers have ever created.

And now my friend Stuart who runs Astronomy Blog has done it one better: he’s created an H-R diagram of media stars. It’s awesome:

That’s really funny, and I wish I had thought of it. The vertical axis is fame, as denoted by Google results, and the horizontal axis is peer-reviewed papers. I’m actually only first author on I think two papers, but I was listed as author on a lot due to my work on Hubble. So I do OK on this diagram. I note that Brian Cox is more luminous than me, but then, he’s an actual rock star. If there were a branch for white main sequence stars, he and I would be in a dead heat.

Next up, I hope: a space-time diagram showing warping due to massive astronomers.

Today’s sewage is tomorrow’s rocket fuel–at least, according to Stanford researchers. Raw sewage has long posed a problem for scientists who aim to get rid of it. That’s because the chemical byproduct of the bacteria that break down waste is nitrous oxide–a greenhouse gas also known as laughing gas.

The proposed solution? Using the nitrous oxide produced by waste as rocket fuel, of course, according to Popular Science:

“[The] rocket thruster, which was designed for use in spacecraft, can consume the excess nitrous oxide to produce heat. In a Stanford press release, [researcher] Cantwell says the nitrous oxide can heat an engine to almost 3,000 degrees Fahrenheit and expel nitrogen and oxygen at 5,000 feet per second.”

Hot oxygen and nitrogen are far less harmful to the environment than nitrous oxide, and the methane that also is produced can help power other wastewater plants, the researchers say. This method, in which bacteria break down the waste in the absence of oxygen, is faster and cheaper than letting sewage decompose in an oxygenated environment, in which “wastewater treatment plants pump oxygen into a roiling mix of raw sewage, to encourage good bacteria to break down organic matter.”

So the next time you head to the bathroom, remember that your contribution could one day prove valuable to rocket scientists. Just another reason to flush with pride.

Image: flickr / ecsuecsu

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Discoblog: Buzz Aldrin Explains: How to Take a Whiz on the Moon
Discoblog: A Novel Geoengineering Idea: Increase the Ocean’s Quotient of Whale Poop
Discoblog: The Coolest Carnivorous Plant/Toilet Plant You’ll See This Week

Colonel Quaritch and his exoskeleton from Avatar

Science fiction is sometimes a playground to explore what it would be like to have a different body. Most recently, in Avatar and Iron Man 2 we saw people joined to exoskeletons, which are being developed in real life for the military and for rehabilitation. The biomechanics of these exoskeletons are a close mimic of our own but with much more power or size. In Avatar, we also witnessed people experience the novelty of inhabiting a three-meter-tall blue body with movable ears and a neural interface that conveniently doubles as a tail.

But why wait for the shapeshifting future? Corsets and girdles are the best known types of “foundation garments” or “shapewear,” but for me at least, they are more Jane Eyre than Madonna, despite the latter’s use of them in her performances over the past twenty years.

For those who actually use shapewear on a day-to-day basis, the most common types must be the padded bra and shoulder pads. But the past week highlighted two new ways of changing the shape of our body. The first was in a Wall Street Journal article by Rachel Dodes on padded panties that promise to give Beyoncé-level gluteus maximi to the large behind-inclined; the second is from Sylvester Stallone’s comment that “action movies changed radically when it became possible to Velcro your muscles on.”

Three cheers to Stallone for bringing male shapewear to our attention. Besides those sometimes unsettling codpieces we see when we watch ballerinos perform the Nutcracker, it turns out that you can purchase just about as many kinds of shape enhancing undergarments for men–bottoms and tops–as for women. Unlike the “Booty Pops” talked about in the WSJ article, which are available at Walgreens and Bed Bath and Beyoncé Beyond, these are not quite as readily available, however (or so I’m told).

Changing our body and face shape is an old past time, of course but shapewear now seems an especially timely approach as a form of body shaping on the cheap, with no trainer or surgery required. In words that would make the hover-chaired human blimps of Wall-E eat another banana split, these two new types of shapewear have already been tied to freedom from the misery of physical movement. Stallone now realizes that he “didn’t have to go to the gym for all those years,” while Booty Pop’s website celebrates that “No expensive surgery or overpriced trainer required.” This is body-shaping custom-tailored for the calorically abundant and economically depressed times of Homo sedentarius.

The mass embrace of the Booty Pop, to choose my words carefully, hints at a new stance toward the human body as human scaffold. It’s a fitting preamble to the future envisaged by sci-fi, when robotic augmentation or more radical reshaping of our body shape through genetics may come to pass. My personal hope is that I’ll have a chance to be an octopus in some future life, so that I can answer emails with two tentacles while using others for stuffing my clam-hole with deep fried cheese, doing an experiment, and lifting barbells. Or maybe I’ll just get Octobooty Pop instead.

You may be talking and I may be listening, but our brains look strikingly similar.

That’s the conclusion of a study in the Proceedings of the National Academy of Sciences this week. After conducting brain scans of a woman telling a story off the cuff and then of 11 people listening to a recording of her, researchers Greg Stephens and Uri Hasson say they found that the same parts of the brains showed activation at the same time, suggesting a deep connection between talker and listener.

Graduate student Lauren Silbert was the team’s storytelling guinea pig. She recounted tales of high school, like deciding whom to take to prom, while undergoing an fMRI scan.

As Silbert spoke about her prom experience, the same areas lit up in her brain as in the brains of her listeners. In most brain regions, the activation pattern in the listeners’ brains came a few seconds after that seen in Silbert’s brain. But a few brain areas, including one in the frontal lobe, actually lit up before Silbert’s, perhaps representing listeners’ anticipating what she was going to say next, the team says [ScienceNOW].

When the neuroscientists scanned the same listeners while they heard a story in Russian that they couldn’t understand, the coupling of brain regions didn’t show up.

The study certainly comes with caveats: Its sample size is small, and scientists don’t know exactly what causes the synchronization, nor the exact function of the brain regions in question to any more specificity than “language.” But Stephens and Hasson argue that their findings speak to conceptual common ground people must meet to make conversation possible:

“If I say, ‘Do you want a coffee?’ you say, ‘Yes please, two sugars.’ You don’t say, ‘Yes, please put two sugars in the cup of coffee that is between us,’” said Hasson. “You’re sharing the same lexical items, grammatical constructs and contextual framework. And this is happening not just abstractly, but literally in the brain” [Wired.com].

The findings leave neuroscientists with a host of directions in which they could go. Hasson says his team’s next step is to go beyond one talker and a bunch of listeners and actually study people engaged in dialogue.

Related Content:
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DISCOVER: Why Has Steven Pinker Studied Verbs for 20 Years?

Image: iStockphoto

[I know I already posted this, but the video of the trailer had to be taken down, fixed, and put back up, so I'm reposting to give everyone a chance to actually watch it. Everything works now. Yay! Also, it's up on reddit (actually twice) and Fark, too.]

Finally, at last, after many months, I can now officially reveal the Sooper Sekrit Project that has kept me so busy over all this time. I think you’re gonna like this… so why not just jump right in to the teaser trailer posted online by a small TV network you may have heard of called THE DISCOVERY CHANNEL!

[evil laugh]

How ’bout that?

I’ve been working with the Discovery Channel on hosting a new TV science show called "Phil Plait’s Bad Universe". It’s a three-part program where I dissect issues in astronomy and science, putting claims to the test. There’s no air date yet, but I’m hoping it’ll be on your TV sets this fall.

As you can see in the trailer, the first episode is about asteroid impacts, and we tackle the issue in a way that I don’t think has been done on TV. I get right into the mix, blowing things up, flying in a jet, going where the action is so that I can participate in experiments with scientists and try to find out what works and what doesn’t. The idea here is not to have some dry, narrated documentary. Instead I will show you what’s going on, take you along, so that you can see how these things work and what we’re doing to investigate these issues.

I’ve been having a tremendous time filming this, flying around the country, seeing things I ordinarily would never get to see. And the beauty is, you can come too!

Eventually I’ll post some pictures I’ve taken on this adventure, and we’ll be posting more video online as well as more information about the show soon. I’d like to thank everyone at Discovery Channel and Morningstar Entertainment for giving me this chance to fulfill a long-standing dream of mine. We’ve worked very hard on this program, and I hope you like it.

Yay!

Jellyfish may seem like simple blobs but some have surprisingly sophisticated features, including eyes. These are often just light-sensitive pits but species like the root-arm medusa have complex ‘camera’ eyes, with a lens that focuses light onto a retina. Not only are these organs superficially similar to ours, they’re also constructed from the same genetic building blocks.

Hiroshi Suga from the University of Basel has been studying the eyes of the root-arm medusa (Cladonema radiatum). His work strongly suggests that all animal eyes share a common origin, whether they belong to a human or an insect, an octopus or a jellyfish. The details may be different but they’re all under the control of closely related ‘master genes’ that themselves evolved from a common ancestor.

As you might imagine, growing an eye is a complicated business and involves a huge alliance of different genes, switching on and off in a coordinated way. But in humans and other animals, this alliance all comes under the control of a master gene called Pax-6. Pax-6 was discovered in 1994 by Walter Gehring, who also led the current Cladonema study. Faulty copies can cause serious eye problems in animals as diverse as flies and rodents. And activating the gene in the wrong part of the body can produce eyes where they really shouldn’t exist, like the leg of a fly.

Pax-6 is so important that it’s largely the same in very distantly related animals (the technical term is ‘conserved’). You can take the version of Pax-6 from a mouse and shove it into a fly, and it will still be able to trigger the development of an eye. Even though these misplaced eyes have been activated by a mouse gene, they have the compound structure of typical fly eyes. This underlies the role of Pax-6 as a conductor – its job is to coordinate an orchestra of other eye-producing genes.

Pax-6 is just one of a number of closely related Pax genes. Cladonema doesn’t have a direct equivalent of Pax-6 but it does have three Pax genes of its own, each belonging to a distinct lineage. Only one of these – Pax-A – is actually active in the eyes and Suga clearly showed it’s the jellyfish’s master eye gene. When he transferred it into a fruit fly, he managed to trigger the development of eyes on odd body parts.

Cladonema isn’t the only jellyfish with complex eyes. Another one called Tripedelia belongs to a different group of jellies altogether and it too has a master eye gene called Pax-B, which belongs to a different group to either Pax-A or Pax-6. These three groups of genes evolved shortly after the very dawn of animal evolution from a single ancestral gene that duplicated itself several times. Its copies diverged into the different Pax groups.

So three groups of animals build their eyes using related master eye genes: the hydrozoan jellyfish, represented by Cladonema, use Pax-A; the cubozoan jellies, represented by Tripedelia, use Pax-B; and the bilaterians, including humans and the vast majority of other animals, use Pax-6.

You could argue that this means animal eyes evolved independently at least three times. But Suga disagrees – if this was the case, you might expect the master genes to be recruited from different gene families. As it is, they’re all Pax genes. Instead, Suga thinks that the building blocks of all animal eyes share a common origin. It’s a view that runs counter to the common assertion that animal eyes evolved many times independently but it’s one that Gehring has been championing for years.

When the common ancestor of jellyfish and more complex animals initially evolved eyes, Suga thinks they were under the control of several different Pax genes from the various families. As the bilaterians, hydrozoans and cubozoans diverged from one another, their eye programs eventually fell under the control of single Pax genes from different families. This shared origin explains why genes from one Pax group can still perform the role of genes from the others, and why Cladonema’s Pax-A can produce eyes in a fly.

The evolution of Pax genes. 1) An ancestral gene duplicates itself to produce different classes of Pax genes. 2) The ancestral animal eye evolves under the control of several different classes of Pax genes. 3) In three different animal groups, the Hydrozoa and Cubozoa (both jellyfish) and the Bilateria, eye development comes under the control of species Pax genes. 4) Some of the Pax genes in Bilaterians have been altered.

Reference: PNAS http://dx.doi.org/10.1073/pnas.1008389107

More on eye evolution:

• Mantis shrimp eyes outclass DVD players, inspire new technology
• Glowing squid use bacterial flashlights that double as an extra pair of “eyes”
• From day to night – a lesson in eye evolution with the owl monkey
• Nocturnal mammals see in dark by turning displaced DNA into lenses
• Spookfish eye uses mirrors instead of a lens
• ‘Missing link’ flatfish has eye that’s moved halfway across its head
• Jellyfish and human eyes assembled using similar genetic building blocks

If the citation link isn’t working, read why here

Alright!  Now we get to discuss neutrinos without me having to worry about being reduced to my component parts.  And while I think my component parts are lovely, I’m sure you would rather not go there.

Neutrinos are interesting little guys, meaning literally “neutral elementary particle”.  An elementary particle is simply something which is not known to have smaller parts.  We used to believe atoms were the smallest possible units of mass.  Now we know, of course, that “atoms” are whopping HUGE units of mass.

No, it's not "cute" - This was the first ever hydrogen bubble chamber to detect neutrinos

When we start talking about “elementary particles”, you’re really talking about particle physics.  You quickly get into leptons, bosons, positrons, muons, tau neutrinos, and lots of other really cool words you swore in freshman algebra you’d never use.

Guess again.

Particle physics is also where String Theory comes in, but we aren’t playing around in THAT sandbox today.

Okay… here’s the very basics.  You can accept that everything is composed of small parts, right?  I mean, c’mon guys.  You swallowed atomic theory without gagging, right?  You’re just going to have to realize that an atom is the apple, and it can be sliced and diced into all kinds of little parts and pieces.  Some of these parts have a positive charge, some a negative charge, and some are neutral.  Still with me?

You just never realized how very many pieces and parts atoms could be sliced into.

Really, you’re more than half-way there.  You have the concept of atoms down, right?  You have the whole negative/positive/neutral thing going, right?

We’ll leave string theory for another day.

UPDATE:  SOLVED by Steve at 12:33 CDT

Good morning, everyone.  I hope everyone has had a good week, and that you’re all refreshed and ready to riddle.  I’d love to add your name to the bonus riddle list.  If you’re new to the riddles, the people who solve the weekly riddles get first crack at the bonus riddle.  Yesterday’s post gives the riddle rules, if you need to look over them.  Remember all, it’s August 9th.

Moving right along into today’s riddle, you’ll be searching for an object.

This was a singular object, which became two.

It is associated with several important “firsts”.

Many people thought this wasn’t possible, but it was.

Although it seems like yesterday, this took place some thirty years ago.

For a “first”, it was considered, as a whole, a success.

We lost something here due to human error.

And there you are… your clues for today.  Not as many as you might be used to, but we have to get you trimmed down and ready for the bonus riddle!

Good luck.  You know where to find me.

Mexico: Ancient woman suggests diverse migration:

A scientific reconstruction of one of the oldest sets of human remains found in the Americas appears to support theories that the first people who came to the hemisphere migrated from a broader area than once thought, researchers say.
Mexico’s National Institute of Anthropology and History on Thursday released photos of the reconstructed image of a woman who probably lived on Mexico’s Caribbean coast 10,000 to 12,000 years ago. She peeks out of the picture as a short, spry-looking woman with slightly graying hair.

Anthropologists had long believed humans migrated to the Americas in a relatively short period from a limited area in northeast Asia across a temporary land corridor that opened across the Bering Strait during an ice age.

But government archaeologist Alejandro Terrazas says the picture has now become more complicated, because the reconstruction more resembles people from southeastern Asian areas like Indonesia.

I think this gets at the fallacy:

But Gillespie cautioned against comparing a reconstructed face from 10,000 years ago to modern populations in places like Indonesia, which have also probably changed over 10 millennia.

“You have to find skeletons of the same time period in Asia, or use genetic reconstructions, to make a strong connection, and cannot rely on modern populations,” she wrote. “Do we have any empirical data on what Southeast Asian women looked like … 10,000 years ago?”

A few years ago some scholars asserted that Kennewick Man resembled “South Asians.” I’m open to the possibility of a more complex peopling of the Americas, but until we get ancient DNA (something that is very difficult in the USA), it seems rather strange to make assessments of phylogenetic descent based on phenotypic similarities between one ancient specimen and modern populations.

Image Credit: AP Photo/ Mexico’s National Institute of Anthropology and History

PZ Myers now says he knows who “Tom” is. This certainly raises the possibility that someone may soon “out” him. I have not decided to do so, but the matter might be out of my hands. (Jean Kazez, by the way, has a thoughtful post about this.)

If it happens, there may also be a need to say more about “Tom’s” original story–even though, as I’ve already observed, there is no reason to believe it any longer.

We’ll see….