Meiotic recombination & repeats: is the observed association between hotspots and MaLR repeats just a coincidence?

Tuesday, October 09, 2012 — Poster Session I
1:00 p.m. – 3:00 p.m	Natcher Conference Center, Building 45	NIDDK	BIOINFO-10

Authors

• P. P. Khil
• F. O. Smagulova
• K. Brick
• R.-D. Camerini-Otero
• G. V. Petukhova

Abstract

One of the cis-acting factors associated with increased recombination in humans are LTRs of THE-1B repeats, one of the members of the MaLR superfamily of retrotransposons. MaLR retrotransposons are also associated with recombination in mice, but not in the chimpanzee. To further explore an association between MaLR retrotransposons and meiotic hotspots we performed a detailed analysis of the relative distribution of DSB hotspots and repeats in two strains of mouse with different alleles of PRDM9. We find that MaLR repeats are 3 to 4 fold more frequent in hotspots in the 13R strain but not in C57BL6/J mice. Next, we have generated a DSB hotspot maps of two strains of rat with distinct variants of PRDM9. We find that in rat, as in mouse, one of the alleles of PRDM9 is co-associated with MaLR retrotransposons, while the other is not. Thus, some but not all alleles of PRDM9, recognize LTRs of MaLR retrotransposons and explain inconsistent patterns of the observed association between repeats and DSB hotspots in different species. This association repeatedly emerged over long evolutionary periods (human, mouse, rat), but is not universally conserved. This finding highlights a tight and unexpected co-evolution of MaLR repeats and meiotic recombination.

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