Menschen sind global verbreitet aber lokal evoluiert, heißt es im Titel eines neuen New York Times-Artikels (von Nicholas Wade - "Humans Have Spread Globally, and Evolved Locally") (NYT, Gene Expession). Das war ja auch schon das Thema des Buches von N. Wade "Before the Dawn", das im letzten Jahr erschienen ist. Nun referiert er einige neu hinzugekommene Forschungen, die das bisherige bestätigen und erweitern. Der Artikel hat auch eine schöne Grafik, die den Inhalt bildlich veranschaulicht (vielleicht wird's durch Draufklicken größer, sonst muß man zur Original-Seite gehen):
Einige Textauszüge (Hervorhebungen durch mich, I.B.):
(...) Another study, by Scott Williamson of Cornell University and colleagues, published in PLoS Genetics this month, found 100 genes under selection in Chinese, African-Americans and European-Americans.
In most cases, the source of selective pressure is unknown. But many genes associated with resistance to disease emerge from the scans, confirming that disease is a powerful selective force. Another category of genes under selective pressure covers those involved in metabolism, suggesting that people were responding to changes in diet, perhaps associated with the switch from hunting and gathering to agriculture.
Außerdem gibt es Gene, die die Hautfarbe kodieren. - Und hier dann etwas für unsere kritische Kommentatorin Sinuhe (aber natürlich nicht nur für sie!):
Another puzzle is presented by selected genes involved in brain function, which occur in different populations and could presumably be responses to behavioral challenges encountered since people left the ancestral homeland in Africa.
But some genes have more than one role, and some of these brain-related genes could have been selected for other properties.
Hierüber werden zunächst ältere Forschungen referiert (Bruce Lahn) und dann heißt es:
Even more strikingly, Dr. Williamson’s group reported that a version of a gene called DAB1 had become universal in Chinese but not in other populations. DAB1 is involved in organizing the layers of cells in the cerebral cortex, the site of higher cognitive functions.
Variants of two genes involved in hearing have become universal, one in Chinese, the other in Europeans.
Das könnte wieder etwas zu tun haben tonalen und nicht-tonalen Sprachen (siehe St. gen.). Außerdem gibt es Implikationen für Historiker, bzw. historische Implikationen für Humangenetiker:
The emerging lists of selected human genes may open new insights into the interactions between history and genetics. “If we ask what are the most important evolutionary events of the last 5,000 years, they are cultural, like the spread of agriculture, or extinctions of populations through war or disease,” said Marcus Feldman, a population geneticist at Stanford. These cultural events are likely to have left deep marks in the human genome. (...)
The clusterings reflect “serial founder effects,” Dr. Feldman said, meaning that as people migrated around the world, each new population carried away just part of the genetic variation in the one it was derived from.
Zeitlich nacheinander geschaltete Gründereffekte - na, hab ich das nicht immer schon gesagt? Einer der letzten Gründereffekte betraf das aschkenasische Judentum, also einige wenige Frauen, die vor tausend Jahren am Rhein gelebt haben, und von denen heute mehrere Millionen aschkenasische Juden weltweit abstammen. Gründereffekte (also "Flaschenhals-Populationen") sind immer besonders gut geeignet, um neue Gene zu selektieren - zum Beispiel auch IQ-Gene.
Einige Textauszüge (Hervorhebungen durch mich, I.B.):(...) Another study, by Scott Williamson of Cornell University and colleagues, published in PLoS Genetics this month, found 100 genes under selection in Chinese, African-Americans and European-Americans.
In most cases, the source of selective pressure is unknown. But many genes associated with resistance to disease emerge from the scans, confirming that disease is a powerful selective force. Another category of genes under selective pressure covers those involved in metabolism, suggesting that people were responding to changes in diet, perhaps associated with the switch from hunting and gathering to agriculture.
Außerdem gibt es Gene, die die Hautfarbe kodieren. - Und hier dann etwas für unsere kritische Kommentatorin Sinuhe (aber natürlich nicht nur für sie!):
Another puzzle is presented by selected genes involved in brain function, which occur in different populations and could presumably be responses to behavioral challenges encountered since people left the ancestral homeland in Africa.
But some genes have more than one role, and some of these brain-related genes could have been selected for other properties.
Hierüber werden zunächst ältere Forschungen referiert (Bruce Lahn) und dann heißt es:
Even more strikingly, Dr. Williamson’s group reported that a version of a gene called DAB1 had become universal in Chinese but not in other populations. DAB1 is involved in organizing the layers of cells in the cerebral cortex, the site of higher cognitive functions.
Variants of two genes involved in hearing have become universal, one in Chinese, the other in Europeans.
Das könnte wieder etwas zu tun haben tonalen und nicht-tonalen Sprachen (siehe St. gen.). Außerdem gibt es Implikationen für Historiker, bzw. historische Implikationen für Humangenetiker:
The emerging lists of selected human genes may open new insights into the interactions between history and genetics. “If we ask what are the most important evolutionary events of the last 5,000 years, they are cultural, like the spread of agriculture, or extinctions of populations through war or disease,” said Marcus Feldman, a population geneticist at Stanford. These cultural events are likely to have left deep marks in the human genome. (...)
The clusterings reflect “serial founder effects,” Dr. Feldman said, meaning that as people migrated around the world, each new population carried away just part of the genetic variation in the one it was derived from.
Zeitlich nacheinander geschaltete Gründereffekte - na, hab ich das nicht immer schon gesagt? Einer der letzten Gründereffekte betraf das aschkenasische Judentum, also einige wenige Frauen, die vor tausend Jahren am Rhein gelebt haben, und von denen heute mehrere Millionen aschkenasische Juden weltweit abstammen. Gründereffekte (also "Flaschenhals-Populationen") sind immer besonders gut geeignet, um neue Gene zu selektieren - zum Beispiel auch IQ-Gene.
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