Genes

Gene popsicles

In the Dry Valleys of the Transantarctic Mountains there are pockets of ice up to 8 million years old. Last week, scientists announced that they resuscitated microbes from this ice. If the microbes are as old as the ice, they were around long before humans split from the chimpanzee/bonobo line, approximately 6 million years ago. The scientists call their sample a "gene popsicle" and speculate that in periods of the Earth's history when ancient ice melted, microbes in samples like theirs might have been reincorporated into current populations--which might be something like dating your great- great- great- to-the-1000th grandmother. They also wonder if the preservation of microbes in icy comets may have seeded planets with genetic material as distant in space as well as time. PNAS, National Geographic.


Humanity's first home

Modern humans originated in Sub-saharan Africa, and from there spread all over the globe. Cambridge scientists, who published their study today in Nature, used genetic information combined with the measurements of 6000 skulls from collections all over the world in order to confirm what's known as the 'Out of Africa' theory. The idea of African origins for humans has become very widely accepted over the last ten or so years--this new study deals a final blow to scholars hanging onto the notion that humans may have originated in separate locations all over the world. SciAM.


Did they or didn't they?

Did Neandertals and humans interbreed? Every couple of years this question cycles through the press, generally instigated by a scientific article presenting new evidence either way. Erik Trinkaus, who compares the bones of ancient humans and Neandertals, is the best known for arguing that they did. Most recently, Spencer Wells of the Genographic Project, told Wired magazine there was no evidence in the human genome that Neandertals and their European human contemporaries produced any children.
Trinkaus in PNAS.


Neandertal Park

Since last year when researchers announced their goal of reconstructing the Neandertal genome, the story has been getting play from many angles in all sorts of publications. In the team's most recent announcement, covered pretty much everywhere by everyone, they explain that the kinds of mistakes they might make trying to read ancient DNA are restricted to a few types. Knowing this should help the scientists avoid them. Part of the solution involves using DNA from many Neandertal individuals.
SciAm, ABCnews,


Evolution Special

The New York Times Science section has an excellent evolution special this week. Of particular interest is Nicholas Wade's article on the very recent evolution of human populations. There is more and more evidence that culture has shaped the human genome. Also fascinating is Cornelia Dean's inquiry into what has happened to the human soul. Evolve locally, Science of the Soul.


Small Genetic Differences, Big Language Effects

Two variants of the genes ASPM and Microcephalin may make it easier to learn tone languages. If you have the tone-versions, as do most speakers of Chinese (and other languages such as those found in South East Asia and sub-Saharan Africa), you may be more adept at learning languages that distinguish words with pitch as opposed to those that don't. This is the first time it's been shown that possessing a particular form of gene, let alone two, may impact the way we learn language.  The dogma has always been that we are all born with precisely the same genetic program which builds exactly the same neural equipment for language. The Times, Scientific American, PNAS.