The Economist today highlights a few of the recent super science (AAAS) meeting.
Cooking is humanity's "killer app" (emphases mine) underscores that we are not natural, we are a creation of our own technology. Perhaps cooking is the oldest profession ...
...without cooking, the human brain (which consumes 20-25% of the body’s energy) could not keep running. Dr Wrangham thus believes that cooking and humanity are coeval.
In fact, as he outlined to the American Association for the Advancement of Science (AAAS), in Chicago, he thinks that cooking and other forms of preparing food are humanity’s “killer app”: the evolutionary change that underpins all of the other—and subsequent—changes that have made people such unusual animals...
...even modern “raw foodists”, members of a town-dwelling, back-to-nature social movement, struggle to maintain their weight—and they have access to animals and plants that have been bred for the table. Pre-agricultural man confined to raw food would have starved...
...Dr Wrangham suspects the main cause of the modern epidemic of obesity is not overeating (which the evidence suggests—in America, at least—is a myth) but the rise of processed foods. These are softer, because that is what people prefer. Indeed, the nerves from the taste buds meet in a part of the brain called the amygdala with nerves that convey information on the softness of food. It is only after these two qualities have been compared that the brain assesses how pleasant a mouthful actually is....
What goes into a dog breed emphasizes how plastic our forms are, and how fungible ...
Dr Ostrander has already used dogs to track down the genes behind certain cancers that the species shares with people, and to work out the dog family tree. At the AAAS she described her search for the genes controlling three of the most important features of a breed: its size, its hair and the length of its legs...
... The size of water dogs, she found, is governed mainly by variations in a gene called insulin-like growth-factor 1—and that is probably true of other breeds as well...
...Short legs, a phenomenon known as chondrodysplasia, are characteristic of many dog breeds, perhaps most famously dachshunds and corgis. In people the condition is known vulgarly as dwarfism. Dr Ostrander’s work showed that in dogs it is caused by the reactivation of a “dead” version of a gene involved in the regulation of growth. Chromosomes are littered with such non-functional genes; they are the result of mutations favoured by natural selection at some point in the past. Here the gene in question has been reactivated by the arrival within it of what is known as a LINE-1 element. This is a piece of DNA that can jump about from place to place within a genome, sometimes causing havoc as it does so....
...Dr Ostrander found that 80% of the variation between breeds in coat form and furniture was explained by differences in just three genes. Different combinations of these result in different mixtures of coat and furniture...
Now that you're thinking about how a few gene variations can cause amazing changes to shape and size, you're prepared to contemplate another genome ... that of our brother Neandertal ...
Svante Paabo of the Max Planck Institute for Evolutionary Anthropology, in Leipzig, chose Darwin’s 200th anniversary to announce what would, until recently, have been thought an impossible discovery in evolutionary biology—a draft of the genome of Neanderthal man.
Dr Paabo made his announcement to the AAAS meeting via a video link from Germany, and followed it up by a lecture in person on the 15th. The Neanderthal Genome Project, as it is known, is the culmination of a career devoted to the examination of ancient DNA by a man whose work provided inspiration for Michael Crichton’s novel and film “Jurassic Park”...
...one-fold coverage gives you about 60% of the genome, and that is what Dr Paabo’s first draft has achieved...
...the Neanderthal line and that of modern humanity parted company only shortly before the oldest known Neanderthal fossils were alive...
...The team has also looked at a few genes of particular interest. The most famous of these is FOXP2, damage to which prevents speech in modern humans. Neanderthals turn out to have the same version of FOXP2 as Homo sapiens (and thus a different one from chimpanzees). Researchers are divided about how significant FOXP2 really is, because it is involved in the mechanics of speech production, not the mental abilities that lie at the root of language. But some regard this discovery as evidence that Neanderthals could speak.
Much more information should emerge as Dr Paabo increases his one-fold coverage to 20-fold, the point at which almost every base pair is represented. At that moment, science will have in its grasp the genetic details of what is probably modern humanity’s closest relative...
Min-pin and Newfie look less alike than Neandertal and us. They cooked, of course, but perhaps not as well as we did ...
No comments:
Post a Comment