| 2. |
- van de Lagemaat, LN, et al.
(författare)
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Genomic deletions and precise removal of transposable elements mediated by short identical DNA segments in primates
- 2005
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1549-5469 .- 1088-9051. ; 15:9, s. 1243-1249
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Tidskriftsartikel (refereegranskat)abstract
- Insertion of transposable elements is a major cause of genomic expansion in eukaryotes. Less is understood, however, about mechanisms underlying contraction of genomes. In this study, we show that retroelements can, in rare cases, be precisely deleted from primate genomes, most likely via recombination between 10- to 20-bp target site duplications (TSDs) flanking the retroelement. The deleted loci are indistinguishable from pre-integration sites, effectively reversing the insertion. Through human-chimpanzee-Rhesus monkey genomic comparisons, we estimate that 0.5%-1% of apparent retroelement "insertions" distinguishing humans and chimpanzees actually represent deletions. Furthermore, we demonstrate that 19% of genomic deletions of 200-500 bp that have occurred since the human-chimpanzee divergence are associated with flanking identical repeats of at least 10 bp. A large number of deletions internal to Alu elements were also found flanked by homologies. These results suggest that illegitimate recombination between short direct repeats has played a significant role in human genome evolution. Moreover, this study lends perspective to the view that insertions of retroelements represent unidirectional genetic events.
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| 3. |
- van de Lagemaat, LN, et al.
(författare)
-
Transposable elements in mammals promote regulatory variation and diversification of genes with specialized functions
- 2003
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Ingår i: Trends in Genetics. - : Elsevier BV. - 1362-4555 .- 0168-9525. ; 19:10, s. 530-536
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Tidskriftsartikel (refereegranskat)abstract
- Nearly half of mammalian genomes are derived from ancient transposable elements (TEs). We analyzed the prevalence of TEs in untranslated regions of human and mouse mRNAs and found evidence suggesting that TEs affect the expression of many genes through the donation of transcriptional regulatory signals. Furthermore, we found that recently expanded gene classes, such as those involved in immunity or response to external stimuli, have transcripts enriched in TEs, whereas TEs are excluded from mRNAs of highly conserved genes with basic functions in development or metabolism. These results support the view that TEs have played a significant role in the diversification and evolution of mammalian genes.
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