Donnerstag, Dezember 08, 2005

New York Times - das Genom der Hunde

Aus der heutigen New York Times - jetzt kennen die Forscher endlich das Genom der Hunde - wozu auch immer das gut sein mag ...

Researchers Decode Dog Genome

By NICHOLAS WADE
Published: December 7, 2005
Researchers have decoded the dog genome to a high degree of accuracy, allowing deep insights into the evolutionary history not only of Canis familiaris but also of its devoted companion species, Homo sapiens.
The dog whose genome has been sequenced is Tasha, a female boxer whose owners wish to remain anonymous, said Kerstin Lindblad-Toh, a biologist at the Broad Institute in Cambridge who led a large group of colleagues in the DNA sequencing effort. Their findings are being reported in Thursday's issue of the journal Nature.
The world's dog population numbers some 400 million, divided into about 400 breeds. The researchers chose to sequence Tasha's genome because boxers are quite inbred, easing the decoding task, and because since she is a female, they did not have to bother with a Y chromosome, whose long palindromic regions make it particularly hard slogging.
One insight that has emerged from having a fairly complete dog genome, in addition to those for humans and mice, is that researchers can begin to see the essence of what makes a mammal. The same 5 percent of DNA is conserved in all three species, and this presumably is evolution's basic toolkit for constructing a generic mammal.
Of this conserved tool kit, some 2 percent consists of known genes and the rest of something else, presumably the regulatory elements of DNA that control the operation of the protein-encoding genes, Dr. Lindblad-Toh said.
The conserved genes probably include those deployed during development to construct the organism, But many regulatory elements also seem to be needed, so as to orchestrate an elaborate succession of genes being switched off and on as new tissues and organs are generated.
Another finding that has emerged from a three-way comparison of dog, mouse and human is that genes for brain function seem to have evolved faster than others in both dogs and people. This could be because social animals may need extra computing power to recognize one another and predict one another's behavior.
One group of genes that has been under particular selective pressure in the human line are those that govern male reproduction, evidence of the importance of sexual selection in primate evolution.

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