Functional requirements driving the gene duplication in 12 Drosophila species.
BACKGROUND
Gene duplication supplies the raw materials for novel gene functions and many gene families arisen from duplication experience adaptive evolution. Most studies of young duplicates have focused on mammals, especially humans, whereas reports describing their genome-wide evolutionary patterns across the closely related Drosophila species are rare. The sequenced 12 Drosophila genomes provide the opportunity to address this issue.


RESULTS
In our study, 3,647 young duplicate gene families were identified across the 12 Drosophila species and three types of expansions, species-specific, lineage-specific and complex expansions, were detected in these gene families. Our data showed that the species-specific young duplicate genes predominated (86.6%) over the other two types. Interestingly, many independent species-specific expansions in the same gene family have been observed in many species, even including 11 or 12 Drosophila species. Our data also showed that the functional bias observed in these young duplicate genes was mainly related to responses to environmental stimuli and biotic stresses.


CONCLUSIONS
This study reveals the evolutionary patterns of young duplicates across 12 Drosophila species on a genomic scale. Our results suggest that convergent evolution acts on young duplicate genes after the species differentiation and adaptive evolution may play an important role in duplicate genes for adaption to ecological factors and environmental changes in Drosophila.
State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, 22 Hankou Rd, Nanjing 210093, China.
Yan
Y
Zhong
Yanxiao
Y
Jia
Yang
Y
Gao
Dacheng
D
Tian
Sihai
S
Yang
Xiaohui
X
Zhang
D000818:Animals; D059006:Chromosomes, Insect / Q000235:genetics; D004330:Drosophila / Q000235:genetics*; D019143:Evolution, Molecular; D020440:Gene Duplication / Q000235:genetics*; D017344:Genes, Insect / Q000235:genetics*; D023281:Genomics; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity