The human genome may have been sequenced back in 2004, but that was a far cry from documenting all the genes inside us. Our bodies are home to a dizzying number and variety of bacteria, and in a study published in this week’s Nature, researchers have used metagenomic sequencing to catalog the genes that belong to the microbes living in our guts.

The project, which sampled 124 European people, found that each individual had at least 160 species of bacteria living in his or her digestive tract, and there’s a lot of overlap between our guts. At least 57 species of bacteria were present in just about everybody. Overall, the researchers cataloged about 1,000 different bacteria species and figure there’s another 150 or so they haven’t found [AP].

Researcher Jeroen Raes reminds us that no matter if we’re grossed out by the fact that bacteria infest our body, we depend on them. “The bacteria help digest food, provide vitamins, protect us from invading pathogens. If there’s a disturbance, people get all sorts of diseases such as Crohn’s disease, Ulcerative colitis, and a link has also been made to obesity” [BBC News]. In addition, he says, we have 10 times the number of bacterial cells in our bodies than human cells, and 100 times bacterial genes than our own. So we’re pretty much walking bacteria farms.

It’ll take time to sort out the tangled web of data from all those microbial species. Study coauthor Wang Jun says one of the ultimate goals is to pin down relationships between bacteria and diseases like those that Raes listed. “If you just tackle these bacteria, it is easier than treating the human body itself. If you find that a certain bug is responsible for a certain disease and you kill it, then you kill the disease,” Wang said [Reuters]. Wang is currently working on a similar study in China.

In the meantime, some, like outside researcher Elaine Holmes, were just impressed that this feat could be achieved. “It uses a large number of participants and therefore one assumes it is more representative of the ‘real’ microbial composition than previous studies. Also, it is an amazing feat of data processing” [BBC News].

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Image: iStockphoto

This is the seventh in a series of guest posts by Joel Barkan, a previous contributor to “The Intersection” and a graduate student at the Scripps Institution of Oceanography. The renowned Scripps marine biologist Jeremy Jackson is teaching his famed “Marine Science, Economics, and Policy” course for what may be the last time this year (along with Jennifer Jacquet), and Joel will be reporting each week on the contents of the course.

I don’t want to write a post all about climate change on Chris and Sheril’s blog because my fire-retardant suit is at the cleaners. So I won’t. But I will write about what marine scientists can learn from what climate scientists are doing (no “Oceangate” jokes, please).

Each week, I write in this space about a different threat that will inevitably doom our oceans if we fail to act. But which threat is the most critical? At least climate scientists have agreed on a general consensus: most of the observed warming over the last 50 years is likely due to increased greenhouse gas concentrations as a result of human activities. UC San Diego’s own Naomi Oreskes, in a 2004 Science essay, analyzed nearly a thousand abstracts published in the ISI database between 1993 and 2003 that contained the keywords “climate change.” Three-quarters of them accepted the consensus view and not a single one challenged it. This means climate scientists know the problem (greenhouse gas emissions) and how to address it (reduce emissions). Of course, it’s not that simple, but it’s a basic cause and effect that advocates can rally behind.

It’s not quite so straightforward for marine scientists. Ask one why the oceans are in danger and he’ll say it’s because of overfishing. Ask another and she’ll say it’s because of pollution. Ask a third and the reason will be coastal development. We know we have problems, but we struggle to agree on the most pressing. Marine scientists also don’t have something like the Keeling Curve to present as a simple, obvious symbol of human impacts on the oceans. Most importantly, the world lacks something like the Intergovernmental Panel on Climate Change (IPCC) to assess ocean health and inform policy decisions. As a result, the marine conservation movement often feels as unorganized and unfocused as a third grade recess.

Dr. Jackson and Dr. Jacquet have challenged us to brainstorm creative solutions for marine management. The student presenters in this week’s class offered some thought-provoking ideas. They cooked up the “Intergovernmental Panel on the Degradation of the Marine Environment,” though Dr. Jacquet suggested substituting “Ocean” for “Marine Environment” to create the snazzy acronym IPDO. Like IPCC does for climate change, IPDO would evaluate the state of the marine environment as a basis for informed policy action. IPDO would also consolidate marine management into a single group, as opposed to the current bewildering myriad of agencies with jurisdiction. The students gave IPDO the hypothetical power to sanction or fine countries for violating certain standards of marine ecosystem health. IPDO would also maintain a points system to evaluate countries based on their protection (or abuse) of the oceans. Every five years or so, IPDO would publish a report on the state of our oceans, much like the IPCC’s Synthesis Report, and reveal which nations were champions of ocean conservation and which were the culprits for ocean degradation. Could the public, international shame of such a ranking motivate the offending countries to change their ways?

At one point, it was suggested that the IPDO could even collaborate with the International Olympic Committee to ban countries from the Games for particularly brazen acts of ocean destruction. Can you imagine if China had been barred from the Vancouver Games for its taste for shark fin soup, or Iceland for its high seas bottom trawling? It’s a crazy idea, but it’s going to take a lot of crazy ideas to thwart the barrage of threats to our oceans.

If you came across the number 1,000,000,000,000,000,000,000,000,000, which is a one followed by 27 zeroes, won’t you say that’s a hella lot of numbers?

UC Davis student Austin Sendek seems to think so. He has initiated a Facebook campaign to designate a scientifically accepted prefix for this number, 10^27. The prefix he chose is “hella” because it is “a hell of a lot” of numbers. It is also his way of mixing homegrown California slang with science. Sendek thinks the new prefix would be the best way to acknowledge the Golden State’s hella hot contributions to science.

If Sendek’s proposal is accepted, then hella would come right after “yotta.”

Physics World reports:

Yotta (10²⁴), which was established in 2001, is currently the largest number established in the International System of Units (SI) — the world’s most widely used system of measurement — with zeta (10²¹), exa (10¹⁸) and peta (10¹⁵) following close behind.

Already, Sendek’s Facebook fan page for the new designator has racked up a huge following, with more than 30,000 fans.

Yeah, Zach’s pretty close on this one…

… but who knows? Maybe things’ll change for science on TV. Maybe sometime soon.

“Previous studies have found that women with larger breasts than the average were considered to be more physically attractive. In these studies attractiveness was measured with the help of silhouette figures or photographs and the effect of breast size on men’s behaviour was not considered. In this study two experiments were carried out in order to test the effect of a woman’s breast size on approaches made by males. We hypothesized that an increase in breast size would be associated with an increase in approaches by men. A young female confederate was instructed to wear a bra that permitted her to artificially vary her breast size. In the first experiment the female confederate was instructed to sit in a nightclub for one hour whereas in the second experiment she was instructed to take a seat in a pavement area of a bar. It was found that increasing the breast size of the female confederate was associated with an increasing number of approaches by men.”

Photo: flickr/Cane Rosso

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Discoblog: NCBI ROFL: Eye Tracking of Men’s Preferences for Female Breast Size and Areola Pigmentation.