Origin and evolution of new exons in rodents

Research output: Contribution to journalJournal articlepeer-review

  • Wen Wang
  • Hongkun Zheng
  • Shuang Yang
  • Haijing Yu
  • Jun Li
  • Huifeng Jiang
  • Jianning Su
  • Lei Yang
  • Jianguo Zhang
  • Jason McDermott
  • Ram Samudrala
  • Jian Wang
  • Huanming Yang
  • Jun Yu
  • Kristiansen, Karsten
  • Gane Ka-Shu Wong
  • Jun Wang
Gene number difference among organisms demonstrates that new gene origination is a fundamental biological process in evolution. Exon shuffling has been universally observed in the formation of new genes. Yet to be learned are the ways new exons originate and evolve, and how often new exons appear. To address these questions, we identified 2695 newly evolved exons in the mouse and rat by comparing the expressed sequences of 12,419 orthologous genes between human and mouse, using 743,856 pig ESTs as the outgroup. The new exon origination rate is about 2.71 x 10(-3) per gene per million years. These new exons have markedly accelerated rates both of nonsynonymous substitutions and of insertions/deletions (indels). A much higher proportion of new exons have K(a)/K(s) ratios >1 (where K(a) is the nonsynonymous substitution rate and K(s) is the synonymous substitution rate) than do the old exons shared by human and mouse, implying a role of positive selection in the rapid evolution. The majority of these new exons have sequences unique in the genome, suggesting that most new exons might originate through "exonization" of intronic sequences. Most of the new exons appear to be alternative exons that are expressed at low levels.
Original languageEnglish
JournalGenome Research
Volume15
Issue number9
Pages (from-to)1258-64
Number of pages6
ISSN1088-9051
DOIs
Publication statusPublished - 2005
Externally publishedYes

Bibliographical note

Keywords: Alternative Splicing; Animals; Base Sequence; DNA; Evolution, Molecular; Exons; Expressed Sequence Tags; Humans; Introns; Mice; Phylogeny; Rats; Rodentia; Sequence Deletion; Sequence Homology, Nucleic Acid; Species Specificity; Time Factors

ID: 11230832