Genomewide comparative analysis of the highly abundant transposable element DINE-1 suggests a recent transpositional burst in Drosophila yakuba.
DINE-1 (Drosophila interspersed element) is the most abundant repetitive sequence in the Drosophila genome derived from transposable elements. It comprises >1% of the Drosophila melanogaster genome (DMG) and is believed to be a relic from an ancient transpositional burst that occurred approximately 5-10 MYA. We performed a genomewide comparison of the abundance, sequence variation, and chromosomal distribution of DINE-1 in D. melanogaster and D. yakuba. Unlike the highly diverged copies in the DMG (pairwise distance approximately 15%), DINE-1's in the Drosophila yakuba genome (DYG) have diverged by only 3.4%. Moreover, the chromosomal distribution of DINE-1 in the two species is very different, with a significant number of euchromatic insertions found only in D. yakuba. We propose that these different patterns are caused by a second transpositional burst of DINE-1's in the D. yakuba genome approximately 1.5 MYA. On the basis of the sequence of these recently transposed copies, we conclude that DINE-1 is likely to be a family of nonautomomous DNA transposons. Analysis of the chromosomal distribution of two age groups of DINE-1's in D. yakuba indicates that (1) there is a negative correlation between recombination rates and the density of DINE-1's and (2) younger copies are more evenly distributed in the chromosome arms, while older copies are mostly located near the centromere regions. Our results fit the predictions of a selection-transposition balance model. Our data on whole-genome comparison of a highly abundant TE among Drosophila sibling species demonstrate the unexpectedly dynamic nature of TE activity in different host genomes.
Yang
Hsiao-Pei
HP
Faculty of Life Sciences & Institute of Genome Sciences, National Yang-Ming University, Peitou, Taipei 112, Taiwan, Republic of China. hpyang@ym.edu.tw
Hung
Tzu-Ling
TL
You
Tzung-Lin
TL
Yang
Tzung-Han
TH
D000818:Animals; D002875:Chromosomes / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics*; D004330:Drosophila / Q000145:classification / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics; D019143:Evolution, Molecular; D018628:Gene Dosage / Q000235:genetics; D049750:Genome, Insect / Q000235:genetics*; D023281:Genomics; D013997:Time Factors
D004251:DNA Transposable Elements