The evolution of short indels at meiotic recombination hotspots
Sprache des Vortragstitels:
Society for Molecular Biology and Evolution (SMBE) meeting
Sprache des Tagungstitel:
Meiosis drives the rapid sequence evolution at recombination hotspot caused by the double-strand breaks that introduce de novo mutations or biased gene conversion at heteroduplexes during mismatch repair. Analyses on the rapid sequence evolution at hotspots have mainly focused on single nucleotide polymorphisms, but very little is known about the evolution of microsatellites at hotspots. Although the evidence correlating microsatellites with hotspots has been inconclusive, it has been reported that short indels are suppressors of recombination. Here, we have analysed the transmission of microsatellites at a recombination hotspot on chromosome 16 at two heterozygous mononucleotide repeats; (A7/A6) and (A22/A12). For this purpose, we have collected a large number of molecules of both crossover products by pooled sperm typing in several donors, and analyzed the crossover breakpoints with TaqMan?PCR and Sanger sequencing. We observed that the microsatellite (A22/A12) located 151 bp upstream from the hotspot center diminishes the breakpoint exchanges and show a reduced recombination frequency, while at the mononucleotide repeat (A6/A7) located 492 bp further upstream, we observed an overtransmission of the insertion over the deletion. It is possible that the position of the indels in relation to the hotspot or double-strand break center seems to influence the transmission of the repeats. Although more data is needed to verify these trends, the analysis of the transmission of a large number of single crossover products can provide important insights into human meiotic recombination biases.