Incredible Animal Adaptations

Greg Laden reports that scientists have sequenced the genome of the Tammar Wallaby, which boasts “the longest period of embryonic diapause of any known mammal, highly synchronized seasonal breeding and an unusual system of lactation.” The new research “provides a hitherto lacking understanding of marsupial gene evolution and hopes to have identified marsupial-specific genetic elements.” Dr. Dolittle shares more amazing research on Life Lines, telling us seals can cool off their brains while diving to conserve oxygen. They do this by shunting blood “to large superficial veins allowing heat to escape to the environment” instead of “routing the blood through arterio-venous heat exchangers.” And on The Weizmann Wave, researchers conclude fruit bats use more than echolocation to navigate after gluing tiny GPS transmitters to their backs. Bats released 84 kilometers from home made straight for their old haunts—as soon as they had a line of sight. This suggests bats “watch for prominent visual landmarks” to “judge their distance and mentally triangulate their positions,” and could even “sense directional sea breezes or magnetic fields.”

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Refusing to Yield

To judge by its name, cancer may seem like a monolithic disease. But a recent study which sequenced the genomes of seven prostate cancers reveals just how staggeringly complex the disease can be. The sequencing revealed not only DNA mutations, but rampant rearrangements of the chromosomes themselves. As ERV explains, “we arent talking a mutation here, a tiny deletion there—we are talking huge chunks of DNA in the wrong place.” Once a cell becomes cancerous—which is no simple transition—it no longer functions as part of a bodily community. Instead, it founds its own community of cellular opportunists. Orac writes, “individual cancers are made up of multiple different clones of cancer cells under selective pressure to become ever more invasive and deadly.” And the evolutionary pressures of the human body can generate some grotesque cells indeed. Like all life, cancer is adaptive and diverse, and refuses to yield. But so, of course, do we.

Endless Frontiers of Science

i-c52f334d7a810c32036501d75d7e32a5-frontbuzz.jpgScience is knowledge, and knowledge can inspire certainty. But certainty, as much a fruit of science, can be its enemy. Whatever wonders may meet the eye, there has always been more to the world. On Oscillator, Christina Agapakis explores the frontiers of synthetic biology, where researchers hope to manufacture “altered proteins or entirely different biological polymers” by creating a “parallel genetic code” that uses four-letter codons instead of three. On Starts With A Bang!, Ethan Siegel recounts two centuries of paradigm shifts, and asks what the next “new” law of nature will be. Can protons decay? Does supersymmetry exist? Are quarks composed of even more elementary particles? And on The Island of Doubt, James Hrynyshyn writes that even the most fundamental tenets of our knowledge have “scientists poking around the edges, looking for flaws in the ointment.” James dismisses the idea “that the science of anthropogenic global warming is ‘settled.’ It isn’t and never will be.”

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African and Human Diversity

i-795d7c64681125a1a87554a431be76ec-divbuzz.jpgOn Not Exactly Rocket Science, Ed Yong reports that two new human genomes have been sequenced: that of South African leader Desmond Tutu, and that of !Gubi, a tribal hunter-gatherer. Along with !Gubi, researchers examined the genes of three other Bushmen, and the diversity they observed was “astounding.” Ed writes that there is more genetic variation between any two of these individuals than there is between “a European and an Asian,” and trying “to understand human genetics without understanding Africa is like trying to learn a language by only looking at words starting with z.” On Gene Expression, Razib Khan explains that “all non-Africans likely descend from one migration Out of Africa, so they carried with them only a small proportion of the total genetic variation of the ancient Africans because of the population bottleneck to which they were subjected.” And back on Not Exactly Rocket Science, Ed Yong introduces us to the ancient Inuit “Inuk,” the ninth human to have his genome sequenced before Tutu and !Gubi became ten and eleven.

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Chromosomes, X and Y

i-c391e5995011d135267ae80c0253f87d-somebuzz.jpgOn Neurotopia, Scicurious offers a refresher course on mitosis. This vital process occurs every time a cell divides, as centrosomes pull apart replicated chromosomes with microtubules. Normal cell mechanics limit this “molecular tug of war” to about 50 iterations, meaning we can’t keep splitting chromosomes forever. But we can use meiosis make some babies. On Gene Expression, Razib Khan explains that the X chromosome is relatively scarce since males only carry one copy of it, while all other chromosomes travel in pairs. This makes the X chromosome “more susceptible to stochastic fluctuations in frequency such as random genetic drift,” causing it to exhibit “greater between population variance” than the genome as whole. And on Not Exactly Rocket Science, Ed Yong stands up for X’s puny boyfriend the Y, a chromosome that once jettisoned “around 97% of its original genes.” These days, the human Y chromosome is definitely up to something, having racked up 310 million years worth of evolutionary change in the 6 million years since chimps and humans shared a common ancestor.

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Not Nearly as Simple as Black and White

i-9731e02af7d5b95a69f2c09a45fcb1f5-racebuzz.jpgRacists often cite IQ as a genetically determined trait, attempting to justify and promote their supremacist attitudes. Even if IQ tests do not favor specific cultural or educational standards, is intelligence coded in our genes, or related to the color of our skin? Greg Laden answers an emphatic “no,” explaining that although intelligence may be heritable–that is, passed from generation to generation like a language–there is no evidence that it is specifically inherited, or genetically determined. On Gene Expression, Razib Khan parses data on African-American ancestry, revealing a genetic heritage that is mainly West African and about 20% European. And in a separate post, Khan reminds us that while statistics can characterize groups of people, individuals will differ widely in their genetic constitution and physical appearance. Finally, visit Dr. Isis on On Becoming a Domestic and Laboratory Goddess to see HP’s inadvertently racist face-tracking software in (occasional) action.

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A Fistful of Seeds

i-358b9447415647c819df917edd076bb1-seedbuzz.jpgOn Casaubon’s Book, Sharon Astyk raises her hackles at the sight of Monsanto, a company which over the last century has churned out artificial sweeteners, sulfuric acid, myriad plastics, herbicides such as DDT, the pernicious defoliant Agent Orange, bovine growth hormone, PCBs, and other chemical wonders. Since their first genetic modification of a plant cell in 1982, Monsanto has shifted increasingly to biotechnology, and now control 90% of the world’s seed genetics. Balking against this growing monopoly on our food crops, Astyk advises “Seeds are powerful. Get some good ones, save them and plant them.” On Tomorrow’s Table, Pamela Ronald reports that China has “approved release of the world’s first genetically engineered rice,” and that by 2015 the number of engineered crops will quadruple as Asian and Latin American countries engender global competition for Monsanto’s seedy interests. Finally, lest we deny them the right of reply, Mathew C. Nisbet presents the company in their own words on Framing Science. To wit, “Monsanto’s advanced seeds not only significantly increase crop yields, they use fewer key sources—like land and fuel—to do it. That’s a win-win for people, and the earth itself.”

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