Sequence shortening in the rodent ancestor
A study led by the ICREA researcher Mar Albà, head of the evolutionary genomics research group at IMIM/UPF, clarified the evolution of insertion and deletion accumulation of DNA sequences in different primate and rodent branches. By using the algorithm Prank+F they have observed that, contrary to previous reports, the only branch with a marked deletion to insertion mutational bias, resulting in substantial sequence shortening, is the rodent ancestral branch. It also appears that protein sequences tolerate deletions better than insertions, resulting in an increase in the deletion to insertion ratio for coding sequences in all branches. These results were published in the journal Genome Research. Further research will be applied to identify with more precision when the rodents experienced their greatest DNA loss.
It has been known for some years that short DNA insertions and deletions account for a significant amount of the variation in mammalian genomes and are likely to make an important contribution to species-specific traits. Their importance for medical genetics is highlighted by the fact that they have been implicated in a wide range of human diseases, the archetypal example being the phenylalanine deletion at position 508 in the CFTR protein that results in cystic fibrosis.
Laurie S, Toll-Riera M, Radó-Trilla N, Albà MM. Sequence shortening in the rodent ancestor. Genome Res. 2011 Nov 29