Ewan Birney of the European Bioinformatics Institute (EMBL-EBI), whose Ensembl team performed much of the computational analysis of the genome, explains the importance of the chicken: "We needed to study a genome that is at the right evolutionary distance from humans. Until now, all the fully sequenced genomes have been too closely related or too distant to get the information that we wanted. For example, the mouse genome gave us lots of useful information about coding regions but we were surprised at how much of the junk DNA was almost identical in mouse and human. This is because not enough time has passed since humans and mice diverged from their common ancestor. As a result, we gained very little new insight into the non-coding regions of the human genome."
The chicken genome, on the other hand, turns out to be an invaluable tool for studying the human genome. It is at the ideal evolutionary distance from the human. During the 310 million years since their paths diverged, sequences with important functions, which include genes and their regulatory motifs, have been under pressure not to mutate because changes to the sequence would have detrimental consequences. By contrast, areas of the genome with no function bona fide 'junk' DNA have been under no such pressure, and sufficient time has lapsed for these regions to become quite distinct in the two genomes.
"We found strong conservation in regions of humans th
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Contact: Trista Dawson
dawson@embl.de
49-622-138-7452
European Molecular Biology Laboratory
8-Dec-2004