Genetics

Like monarch butterflies. Apparently, the shimmering dragonfly migrates like the Monarch butterfly, taking three generations to loop across North America: At least three generations make up the annual migration of common green darner dragonflies. The first generation emerges in the southern United States, Mexico and the Caribbean starting around February and flies north. There, those insects lay eggs and die, giving rise to second generation that migrates south until late October. (Some in that second generation don’t fly south until the next year, after overwintering as nymphs.) A third generation, hatched in the south, overwinters there before laying eggs that will start the entire process over again. (from the chart) … An adult darner, regardless of where it was born, is Read More ›

From ScienceDaily: According to a new study led by researchers at The University of Texas at Austin that looked at 10 species of vertebrates, evolution used a kind of universal formula for turning non-monogamous species into monogamous species — turning up the activity of some genes and turning down others in the brain. “Our study spans 450 million years of evolution, which is how long ago all these species shared a common ancestor,” said Rebecca Young, research associate in UT Austin’s Department of Integrative Biology and first author of the study published today in the journal Proceedings of the National Academy of Sciences. The authors define monogamy in animals as forming a pair bond with one mate for at least Read More ›

It’s certainly worth reflecting on: It’s fair to say that PCBs and fluorocarbons have altered the biochemical composition of the food web and the interior of the human body, and in the case of the PFASs, the water we drink. (Some PFASs can even fall with rain.) These have been swift, sweeping changes over the course of just three or four generations, too quick for the slow-grinding machinery of human evolution to adapt. And yet, PCBs and PFASs are now an integral part of the human story. They pass from species to species, from mother to child. They are present from conception to death, and consumed with daily meals and holy feasts. The presence of PCBs alone shapes how humankind Read More ›

If so, it’s remarkable outcome for genome mapping: So it has been dawning on us is that there is no prior plan or blueprint for development: Instructions are created on the hoof, far more intelligently than is possible from dumb DNA. That is why today’s molecular biologists are reporting “cognitive resources” in cells; “bio-information intelligence”; “cell intelligence”; “metabolic memory”; and “cell knowledge”—all terms appearing in recent literature.1,2 “Do cells think?” is the title of a 2007 paper in the journal Cellular and Molecular Life Sciences.3 On the other hand the assumed developmental “program” coded in a genotype has never been described. It is such discoveries that are turning our ideas of genetic causation inside out. We have traditionally thought of cell Read More ›

From ScienceDaily: When a building is damaged, a general contractor often oversees various subcontractors — framers, electricians, plumbers and drywall hangers — to ensure repairs are done in the correct order and on time. Similarly, when DNA is damaged, a molecular general contractor oversees a network of genetic subcontractors to ensure that the diverse cellular tasks needed to protect and repair the genome are carried out correctly and on time. Scientists have known for some time that a master gene named SOG1 acts like a general contractor for repair, coordinating with various genetic subcontractors of the plant cell to mount an effective DNA damage response. But, it wasn’t clear which specific genes were among the subcontractors, nor how SOG1 interacted Read More ›

It was hardly heard of before and hardly widely predicted; now the Darwinian question is, why isn’t it more common? Why? Because there are two conflicting evolutionary forces at work. In the short-term, mixing mitochondria can be beneficial to individuals because the father’s mitochondria, say, can compensate for a harmful mutation in the mother’s mitochondria. But in the long-term, this can impair evolution’s ability to eliminate bad mutations as they are hidden from view. Lane thinks this is why organisms have an astonishingly wide variety of mechanisms for ensuring mitochondria are only inherited from the mother. During the course of evolution, species have repeatedly evolved such mechanisms, lost them and then evolved similar mechanisms again, his team has proposed.Michael Le Read More ›

From ScienceDaily: The birder and biologist was Tom Smith, who has spent his career studying finches — specifically, black-bellied seedcrackers (Pyrenestes ostrinus) — in Cameroon and in his lab at the University of California-Los Angeles. He and his colleagues have spent years investigating why some of these finches have small beaks while others have large beaks. Much of their original work identified differences in the hardness of the seeds they eat, a story quite similar to that of Darwin’s finches. Smith, who is a professor at UCLA as well as the founding director of the Center for Tropical Research, established a breeding colony of these finches to understand the inheritance of beak size. The result was startlingly and elegantly simple: Read More ›

At her blog, Oscillations, Suzan Mazur offers suggestions for panelists and explains why more public input is needed in this area, which is ramping up in the United States: NSF says it cares about the “social and ethical dimensions of such research.” So who gets to say what synthetic cell research meets society’s approval? I think creating a responsible US citizens panel is urgent. … As of now, the NSF plan is to “educate” the American people about synthetic cell development after selections are quietly made by insiders who we don’t know. This approach cannot remain unchallenged. Suzan Mazur, “America Needs a Citizens Panel on Ethics & Synthetic Cell Development” at Oscillations She notes that Germany is taking a more proactive Read More ›

Seventeen individuals from three unrelated multi-generation families have shown the trait (a high level of mtDNA heteroplasmy, ranging from 24 to 76 percent): A new study led by geneticist Taosheng Huang from the Cincinnati Children’s Hospital Medical Centre shows human mitochondrial DNA can be paternally inherited, in a landmark case that started with the treatment of a sick four-year-old boy. The child, who was showing signs of fatigue, muscle pain, and other symptoms, was evaluated by doctors, and tested to see if he had a mitochondrial disorder. When Huang ran the tests – and then ran them again to be sure – he couldn’t make sense of the results that came back. “That’s impossible,” he told NOVA Next. The reason Read More ›

From Nature’s editors: “A move to classify people on the basis of anatomy or genetics” should be abandoned. According to a draft memo leaked to The New York Times, the US Department of Health and Human Services (HHS) proposes to establish a legal definition of whether someone is male or female based solely and immutably on the genitals they are born with. Genetic testing, it says, could be used to resolve any ambiguity about external appearance. The move would make it easier for institutions receiving federal funds, such as universities and health programmes, to discriminate against people on the basis of their gender identity. The memo claims that processes for deciding the sex on a birth certificate will be “clear, grounded Read More ›

Researchers Nigel Goldenfeld and Thomas Kuhlman noticed that “half of the human genome is made up of retrotransposons [jumping genes, “junk DNA”], but bacteria hardly have them at all” and wondered what would happen if they just inserted some: “We thought a really simple thing to try was to just take one (retrotransposon) out of my genome and put it into the bacteria just to see what would happen,” Kuhlman said. “And it turned out to be really quite interesting.” Their results, published in the Proceedings of the National Academy of Sciences, give more depth to the history of how advanced life may have emerged billions of years ago—and could also help determine the possibility and nature of life on Read More ›