Daily Archives: August 8, 2022

North America is home to more horses than any other continent over 19 million, according to some estimates. For most of human history, however, the Americas had no horses at all.

Archaeological evidence indicates that the genus Equus, which includes horses, donkeys, and zebras, evolved in the western hemisphere between 4 and 4.5 million years ago before spreading to Eurasia, only to disappear during a megafauna extinction event at the end of the Pleistocene.

Eurasias horses survived this extinction event, going on to influence the rise and fall of numerous civilizations. The genus millennia-long trip around the globe concluded in the late 15th century, when European explorers unknowingly returned the domesticated horse to its ancestral home.

From here, horses went on to change life in the Americas just as they had in Eurasia. They enabled Hernn Corts and other conquistadores to venture deep into the American heartland, where the animals provided a strategic advantage against the native populations. Horses also played an important role in local post-Columbian economies, which still revolve heavily around ranching.

Although the reintroduction of horses in the western hemisphere is well-documented in historical literature (Corts subordinate Bernal Diaz wrote at length about the steeds that accompanied them on their initial journey), the same cannot be said for archeological excavations or DNA analysis.

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Horse fossils in the New World are hard to come by. They represent only 2.3% of early colonial animal remains found at the Ek Balam site in Yucatan. At the El Japn and Justo Sierra sites, both located in Mexico City, horse fossils are even rarer, representing 1.75% and 0.23% of the total remains, respectively.

Why are these numbers so low? Archeologists think it might have something to do with social status. The colonial sites mentioned above were once used as garbage dumps. Since horses were used for work and transportation rather than consumption, their bodies rarely ended up in the trash.

With that out of the way, the historical literature indicates that the first domestic horses were taken from the Iberian Peninsula (Spain and Portugal) and brought to the Americas via the Caribbean during the late 15th century. Its plausible, but whos to say these sources can be trusted?

To test the hypothesis, a team of researchers from the Florida Museum of Natural History, the University of Florida, and the University of Georgia sequenced the mitochondrial DNA of a late 16th-century horse found near Puerto Real, a colonial port in northern Haiti. Their study not only sheds light on the ancestry of American horses, but also lends credibility to a famous New World myth.

If the historical literature is to be believed, the first horses were brought to the Americas by Christopher Columbus on his second voyage in 1493. In his book Historia general y natural de las Indias, the Spanish historian Gonzalo Fernndez de Oviedo y Valds writes that these horses boarded Columbus ship on the Canary Islands and were subsequently taken to La Isabela, a town located in what is today the Dominican Republic.

Given that most equids are highly adaptable, it did not take long for Columbus horses to spread throughout greater Hispaniola. Within just a few years, the population had grown from a handful of individuals into self-sustaining herds that produced so many offspring that Nicols de Ovando governor of the West Indies could afford to cease importing horses from Iberia.

As the Spanish colonists dispersed into the western hemisphere, so did their horses. By 1520, equids could be found across the Mesoamerican mainland, which comprises the countries of Costa Rica, Nicaragua, Honduras, El Salvador, Guatemala, and Belize. Less than two decades later, horses were roaming as far north as Florida. Those separated from their owners turned feral, only to be redomesticated by the Native Americans of the Great Plains.

Horses could also be found in Puerto Real, where alongside cows they sustained the towns population and economy. Of the 127,000 or so animal remains that have been identified in Puerto Real, however, only eight of them can be attributed to horses. For their study, the researchers from Florida and Georgia analyzed not a complete horse skeleton, but a single tooth actually, a fragment of a single tooth.

Originally, this tooth fragment was attributed to a cow; researchers did not learn it belonged to a horse until they took a closer look at the DNA embedded within. More so than historical literature, DNA gives us a straightforward and highly detailed impression of the ancestry and, consequently, distribution of horses in early colonial America.

The presence of a specific mutation in its mitochondrial DNA shows that the Puerto Real horse belongs to a branch of the equine family that is mostly found in Central Asia and Southern Europe, including the Iberian Peninsula. The branch encompasses a number of breeds, from Caspian ponies to the Maremmano horses of Italy and the Akhal Teke of Turkmenistan. One mystery solved.

The modern-day breed most closely related with the Puerto Real horse is the Chincoteague pony. Also known as Assateague horses, these wild equids can be found on islands off the coast of Virginia and Maryland. Their striking appearance short, stout legs, thick manes, and large bellies may have resulted from the need to adapt to the harsh environments of and limited resources available on their island homes.

While Chincoteague ponies have been extensively studied by conservationists, it is still unclear how they ended up off the New England coast. Oral traditions from the region, popularized by a 20th-century childrens novel called Misty of Chincoteague, claim their ancestors survived a colonial shipwreck.

This legend was previously contested by historians. Since the first British settlers of Virginia and Maryland made no mention of a feral pony population living on the islands, it seems likely that the Chincoteague ponies arrived sometime after the British did. However, because the DNA of the ponies and the Puerto Real horse differ by only six mutations, the legend may have some truth to it after all.

Thats the most exciting possibility, at least. But there is also another, more plausible scenario as well. Beyond folk stories, the study concludes, affinities between early Caribbean horse breeds and the Chincoteague ponies may reflect Spanish efforts to colonize the Atlantic coast of North America.

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DNA analysis shows when and where horses arrived in America - Big Think

Scientists in the UK are developing a new gene-editing tool that they hope could one day provide a cure to inherited heart defects.

The team at the John Radcliffe laboratory in Oxford, England believe they will be able to prevent the development of inherited heart muscle diseases by rewriting faulty genes in people's DNA.

The therapy is aimed at heart muscle conditions called cardiomyopathy and while these abnormalities can vary, they can sometimes cause progressive heart failure, or even death.

Doctors can already trace genetic forms of the disease in families and confirm whether there is a genetic abnormality, but as of yet there is no cure.

Physicians are unable to prevent the disease from weakening the heart until eventually a transplant is needed and those with genetic cardiomyopathies have a 50-50 risk of passing the faulty genes on to each of their children.

The research is being funded by a 30 million (35.6 million) grant from the research charity the British Heart Foundation.

"Depending on the precise physiological abnormality of the level of the heart muscle cells, it affects the heart in a different way. Some of them will cause the heart to be too thick. Some of them cause the heart to pump too weakly, Professor Hugh Watkins, Lead researcher and the head of the project called CureHeart, explained.

He's been investigating how molecular genetics can be used to address inherited causes of heart disease.

They all have in common that they can cause progressive weakening of the heart and progressive heart failure, starting in young ages and progressing through life, sometimes to the point of needing a heart transplant, he said.

The disease has also struck well known sports personalities.

Bolton footballer Fabrice Muamba had a heart attack during a televised FA Cup match from which he has since recovered, and England cricketer James Tayler was forced to retire in 2016 with a similar heart defect to Muamba.

Watkins says the prevalence of cardiomyopathy is not as common as some other heart diseases, but it's still more widespread than many of us realise.

"We know that one in 250 individuals will have this genetic susceptibility in all populations, from all ethnic and racial backgrounds," he said.

There's one particular class of genetic spelling mistake that can cause dilated cardiomyopathy to run in families, but is also responsible for many of the instances where we see heart failure in women after pregnancy or in individuals who drank too much alcohol or after chemotherapy, and that particular genetic defect affects 35 million people globally".

Gene therapies that cut out mutant or incorrect sections of DNA already exist and they have been used in patients for various diseases, but the researchers here are looking for a more precise gene editing tool, Watkins explained.

"In the patients who have these conditions, our heart muscle conditions, everybody has one healthy copy of the gene, but despite that, they get sick and sometimes that's because the faulty copy interferes with the function of the healthy ones, he said.

So we have to specifically target the faulty copy and leave the healthy one alone and that's a harder challenge than some of the other genetic medicines where it would be fine just to take out or manipulate both copies, he added.

One editing tool that is already in use is called CRISPR.

This therapy cuts out a mistake in the gene, but Watkins says what these researchers want to do is rewrite or silence faulty DNA.

"CRISPR cuts the DNA, both strands of the DNA, you could liken it to a pair of scissors. So that's quite good if you want to take out a piece of DNA or inactivate both copies of the gene, said Watkins.

For our particular disorders, we will need more precision than that because we want to manipulate the faulty copy, but leave the healthy copy alone. So where we're exploring genetic editing, we are currently exploring a type of tool called the base editor.

The team at Cureheart investigating the technology counts David Liu Broade amongst their ranks who discovered and developed this tool using chemistry in a laboratory.

As Watkins explains, the therapy can precisely rewrite single letters in a DNA sequence.

Any cure is years away and before any treatment can start, lengthy trials will be needed to test the safety of the therapy.

Watkins says although the aim is to prevent the development of heart disease, the first human trials are likely to be in people who are already in need of a transplant to establish that it works and is safe.

"If we can step in before the heart is badly damaged, then you can absolutely cure it. I don't think we will start there, because to prove it is safe and effective I think the realistic option is we will have to do our first trials in individuals with quite advanced, severe forms of damage from cardiomyopathy. In fact, people who already know they need a heart transplant, he said.

Any risk we have to take is going to be acceptable because they are already in a very risky, vulnerable position, Watkins added.

And then if they get their transplant, we get the heart out, we can explore it in minute detail and really be clear on what that genetic medicine has achieved".

For more on this story, watch the video in the media player above.

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UK scientists are working on a new tool to edit your DNA and cure hereditary heart problems - Euronews

Cast: Fanny ArdantLouis GarrelDylan RobertMarine VacthCaroline Chaniolleau

Geners: Drama

Director: Mawenn

Release Date: Dec 10, 2020

DNA revolves around a woman with close ties to a beloved Algerian grandfather who protected her from a toxic home life as a child. When he dies, it triggers a deep identity crisis as tensions between her extended family members escalate revealing new depths of resentment and bitterness.

Yes, DNA is available on Netflix! One can access the vast library of titles within Netflix under various subscription costs depending on the plan you choose: $9.99 per month for the basic plan, $15.49 monthly for the standard plan, and $19.99 a month for the premium plan.

At the time of writing, DNA is not available to stream on Hulu through the traditional account which starts at $6.99.However, if you have the HBO Max extension on your Hulu account, you can watch additional movies and shoes on Hulu. This type of package costs $14.99 per month.

No, DNA is not streaming on Disney Plus. With Disney+, you can have a wide range of shows from Marvel, Star Wars, Disney+, Pixar, ESPN, and National Geographic to choose from in the streaming platform for the price of $7.99 monthly or $79.99 annually.

You won't find DNA on HBO Max. But if you're still interested in the service, it's $14.99 per month, which gives you full access to the entire vault, and is also ad-free, or $9.99 per month with ads. However, the annual versions for both are cheaper, with the ad-free plan at $150 and the ad-supported plan at $100.

Unfortunately, DNA is not available to stream for free on Amazon Prime Video. However, you can choose other shows and movies to watch from there as it has a wide variety of shows and movies that you can choose from for $14.99 a month.

DNA is not available to watch on Peacock at the time of writing. Peacock offers a subscription costing $4.99 a month or $49.99 per year for a premium account. As their namesake, the streaming platform is free with content out in the open, however, limited.

DNA is not on Paramount Plus. Paramount Plus has two subscription options: the basic version ad-supported Paramount+ Essential service costs $4.99 per month, and an ad-free premium plan for $9.99 per month.

No dice. DNA isn't streaming on the Apple TV+ library at this time. You can watch plenty of other top-rated shows and movies like Mythic Quest, Tedd Lasso, and Wolfwalkers for a monthly cost of $4.99 from the Apple TV Plus library.

No luck. DNA is not available to watch on Direct TV. If you're interested in other movies and shows, Direct TV still has plenty of other options that may intrigue you.

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Where to Watch and Stream DNA Free Online - EpicStream

There were emotions at the 9th Igbo World Festival of Arts and Culture in Staunton Virginia when Americans whose DNA match the Igbo tribe received tribal names to reflect their ancestral home.

The 2-day event which was organized by the Council of Igbo States in America held between July 29 to July 30, 2022 at the Igbo Village of Frontier Museum.

The event is an annual event initiated nine years ago to unite Igbos in diaspora and those in Nigeria.

But the 2022 edition was wrapped with an intrigue which included naming ceremonies for Americans of Igbo descent, the organizer said in a statement sent to THE WHISTLER.

CISA said, Many African Americans were in attendance for the emotional re-union of the cross Atlantic brotherhood. Their families whose DNA testing confirmed their Igbo ancestry received Igbo names based on the 8-day Igbo market week, re-connected with their Igbo brothers and sisters and were officially welcomed back to their Igbo ancestral homeland by elders and traditional titleholders.

It said in the statement that the reconnection of Americans of Igbo descent tells the story of Igbos that separated from their homeland through slavery and resettled in America.

According to the organisers, the Igbos who are now African American descendants have traced their roots back to Igbo lineage and are reconnecting with their living relatives in Nigeria and Diaspora.

The reconnection remains one of the most avowed emotional high points for many in attendance.

Emotional tears were seen in the faces of many that the 400 years old shackles have been broken. It reflects to a large extend the final step in a quest to discover and reconnect with relatives separated by time, space, and distance dating back to the era of slave trade, it added.

The festival also featured world class musical talents, exhibitions, costumed cultural performances, symposium, interactive art, traditional cuisines, fashion show, marriage traditions, masquerades, and carnival rides.

Also there were display of masquerades as well as legendary Igbo dances like the Ohafia/Abam war dance, and the youthful Atiliogwu acrobatic displays entertained the audience.

Dignitaries who witnessed the reunion were: Her Excellency Dr. Mrs. Uzoma Emenike, Ambassador of the Federal Republic of Nigeria to United States, represented by Mrs. Tarela Njokanma and Mr. Anthony Alonwu, Rev. Dr. Albert Sampson from Chicago, who was ordained by Rev. Dr Martin Luther King Jr., former Haitian ambassador to United Kingdom Ambassador. Jean Pillard, John Avoli, of the Government of Virginia, Chairman of World Igbo Congress, Professor Tony Ejiofor, HRH Eze Chibuzor Ngwakwe, Igbo Council of Traditional Title Holders (ICOTTHUSA) and delegates from Jamaican, Trinidad and Tobago, Haiti and Barbados communities.

Original post:
Tears As American Families With Igbo DNA Receive Tribal Names At World Festival In US The Whistler Newspaper - The Whistler Nigeria

Recent research analyzesmathematical models created to deduce conclusions about how evolution works at the level of populations of organisms.

Claudius Ptolemy, an astronomer and mathematician from Alexandria in the second century, had a lofty goal. He wrote the Almagest, a magisterialtreatise that attempts to explain the motion of stars and the motions of planets. Ptolemy devised a sophisticated mathematical universe model that seemed to replicate the motions of the celestial bodies he had been seeing.

Jeffrey Jensen is a researcher in the Biodesign Center for Mechanisms of Evolution at Arizona State University and a professor in the School of Life Sciences with the Center for Evolution & Medicine. Credit: The Biodesign Institute at Arizona State University

Unfortunately, his cosmic plan had a catastrophic weakness at its heart. Ptolemy began his study with the presumption that the Earth was the center of the cosmos, in keeping with the preconceptions of his day. The Ptolemaic universe, which was made up of intricate epicycles to explain the motions of the planets and stars, has long ago been consigned to history books,its conclusions persisted as scientific dogma for more than 1200 years.

No less vulnerable to flawed theoretical methods are the models in the area of evolutionary biology. Evolutionary biology can result in impressive models that fall short of capturing the genuine workings of nature as it develops the bewildering variety of living species on Earth.

A recent study looks at mathematical models created to deduce conclusions about how evolution works at the level of populations of species. The research comes to the conclusion that these models must be built with great caution, avoiding unwarranted starting assumptions, considering the quality of existing knowledge, and staying open to alternative explanations.

Failure to adhere to strict procedures in the construction of null models can result in theories that appear to fit some aspects of the data obtained from DNA sequencing but fall short in accurately elucidating the underlying evolutionary processes, which are frequently extremely complex and multifaceted.

Such theoretical frameworks may offer compelling but ultimately flawed pictures of how evolution actually acts on populations over time, be these populations of bacteria, shoals of fish, or human societies and their various migrations during prehistory.

In the new study, Jeffrey Jensen, a researcher in the Biodesign Center for Mechanisms of Evolution at Arizona State University and professor in the School of Life Sciences with the Center for Evolution & Medicine, leads a group of international luminaries in the field in providing guidance for future research. Together, they describe a range of criteria that can be used to better ensure the accuracy of models that produce statistical inferences in population genomicsa scientific discipline concerned with large-scale comparisons of DNA sequences within and across populations and species.

One of our key messages is the importance of considering the contributions of evolutionary processes certain to be in constant operation (such as purifying selection and genetic drift), before simply relying on hypothesized or rare evolutionary processes as the primary drivers of observed population variation (such as positive selection), Jensen emphasized.

The study was recently published in the journal PLoS Biology.

Population genomics arose as early efforts in the field attempted to reconcile Charles Darwins notion of evolution by means of natural selection with the first inklings of the mechanisms of inheritance, uncovered by the Augustinian monk, Gregor Mendel.

Susanne Pfeifer is a researcher in the Biodesign Center for Mechanisms of Evolution and an assistant professor at the Center for Evolution & Medicine. Credit: The Biodesign Institute at Arizona State University

The synthesis culminated in the 1920s and early 30s, largely thanks to the mathematical work of Fisher, Haldane, and Wright, who were the first to explore how natural selection together with other evolutionary forces would modify the genetic composition of Mendelian populations over time.

Today, studies in population genomics involve the large-scale application of various genomic technologies to explore the genetic composition of biological populations, and how various factors, including natural selection and genetic drift, produce changes in genetic composition over time.

To accomplish this, population geneticists develop mathematical models quantifying the contributions of these evolutionary processes in shaping gene frequencies, use this theory to design statistical inference approaches for estimating the forces producing observed patterns of genetic variation in actual populations, and test their conclusions against accumulated data.

The study of genomic variation focuses on DNA sequence differences among individuals and populations. Some of these variants are critically important for biological function, including mutations responsible for genetic disease, while others have no detectable biological effects.

Such variation in the human genome can take several forms. One common source of variation is known as single nucleotide polymorphisms, or SNPs, where a single DNA letter in the genome is altered. But larger-scale variation in the genome, involving the simultaneous alteration of hundreds or even thousands of base pairs is also possible. Again, some such alterations may play a role in disease risk and survival while many others have no effect.

Natural selection may occur when different variants segregating in a population have a fitness differential relative to one another. By designing and studying mathematical models governing the corresponding gene frequency change and applying those models to empirical data, population geneticists seek to understand the contributing evolutionary processes in a rigorous, quantitative way. Thus, population genetics is often regarded as the theoretical cornerstone of modern Darwinian evolution.

Although the importance of natural selection to the evolutionary process is undeniable, the role of positive selection in increasing the frequency of beneficial variants the potential driver of adaptation is certain to be comparatively rare relative even to other forms of natural selection. For example, purifying selection the removal of deleterious variants from the population is a constantly acting and far more pervasive form of selection.

In addition, there are multiple non-selective evolutionary processes of great importance. For example, genetic drift describes the many stochastic fluctuations inherent to evolution. In large populations, natural selection may act more efficiently in purging deleterious variation and potentially fixing beneficial variation, whereas as populations become smaller genetic drift will be increasingly dominant.

The distinction can be seen in dramatic form when comparing prokaryotic organisms like bacteria with organisms composed of eukaryotic cells, including humans. In the former case, the vast population sizes tend to result in more efficient selection. In contrast, a weaker selection pressure operating in eukaryotes is more permissive to genomic changes, provided that they are not strongly deleterious.

According to the Neutral Theory of Molecular Evolution a new guiding principle of evolutionary theory proposed by the population geneticist Motoo Kimura over 50 years ago most evolutionary changes at the molecular level in real populations are governed not by natural selection, but by genetic drift. The study emphasizes that this critical point is too often missed by evolutionary biologists. As co-author Michael Lynch, director of ASUs Biodesign Center for Mechanisms in Evolution cogently observes, natural selection is just one of several evolutionary mechanisms, and the failure to realize this is probably the most significant impediment to a fruitful integration of evolutionary theory with molecular, cellular, and developmental biology.

The new consensus study further stresses that a failure to consider these alternative evolutionary mechanisms which are certain to be operating, including genetic drift, and incorporate these into models of population genomics, is likely to lead researchers astray. The common overreliance on purely adaptive models to explain genomic variation has led to a raft of interpretations of dubious value, the authors assert.

The study presents a detailed flow chart that can help guide the development of more accurate models used to draw evolutionary inferences, based on genomic data. Biological parameters that vary among species include not only evolutionary variables like population size, mutation rates, recombination rates, and population structure and history but the way the genome itself is structured and life history traits, including mating behavior. All of these factors play a vital role in dictating observed molecular variation and evolution.

While these many considerations may sound daunting for some researchers, it is important to note that many excellent research groups at ASU and around the world are actively improving our understanding of these underlying evolutionary parameters, providing constantly improving inference, for example, of mutation and recombination rates, added co-author Susanne Pfeifer, an Assistant Professor in the Center for Evolution & Medicine and the Biodesign Center for Mechanisms of Evolution.

Where once, theoretical models in population genomics proliferated alongside relatively scant genomic data, today an avalanche of data, enabled by rapid, low-cost DNA sequencing of organisms across the tree of life, has dramatically changed the field. The careful and judicious use of this gold mine of genomic data will help advance the most rigorous models to unlock evolutions many remaining mysteries.

Reference: Recommendations for improving statistical inference in population genomics by Parul Johri, Charles F. Aquadro, Mark Beaumont, Brian Charlesworth, Laurent Excoffier, Adam Eyre-Walker, Peter D. Keightley, Michael Lynch, Gil McVean, Bret A. Payseur, Susanne P. Pfeifer, Wolfgang Stephan and Jeffrey D. Jensen, 31 May 2022, PLoS Biology.DOI: 10.1371/journal.pbio.3001669

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The Pitfalls of Evolutionary Genomics - SciTechDaily