A Phylogeny of Caenorhabditis Reveals Frequent Loss of Introns During Nematode Evolution
AUTOR(ES)
Cho, Soochin
FONTE
Cold Spring Harbor Laboratory Press
RESUMO
Since introns were discovered 26 years ago, people have wondered how changes in intron/exon structure occur, and what role these changes play in evolution. To answer these questions, we have begun studying gene structure in nematodes related to Caenorhabditis elegans. As a first step, we cloned a set of five genes from six different Caenorhabditis species, and used their amino acid sequences to construct the first detailed phylogeny of this genus. Our data indicate that nematode introns are lost at a very high rate during evolution, almost 400-fold higher than in mammals. These losses do not occur randomly, but instead, favor some introns and do not affect others. In contrast, intron gains are far less common than losses in these genes. On the basis of the sequences at each intron site, we suggest that several distinct mechanisms can cause introns to be lost. The small size of C. elegans introns should increase the rate at which each of these types of loss can occur, and might account for the dramatic difference in loss rate between nematodes and mammals.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=442136Documentos Relacionados
- Analysis of the constancy of DNA sequences during development and evolution of the nematode Caenorhabditis elegans.
- Caenorhabditis phylogeny predicts convergence of hermaphroditism and extensive intron loss
- Mode and Tempo of Molecular Evolution in the Nematode Caenorhabditis: Cytochrome Oxidase II and Calmodulin Sequences
- Interspecies Comparison Reveals Evolution of Control Regions in the Nematode Sex-Determining Gene Tra-2
- Origins of recently gained introns in Caenorhabditis