Recombination study by MLH1 immunostaining of mouse spermatocytes after dietary treatments

<p>Meiotic recombination is a critical process for sexually reproducing organisms. This exchange of genetic information between homologous chromosomes during meiosis is important not only because it generates genetic diversity, but also because it is often required for proper chromosome segregation. Consequently, the frequency and distribution of crossovers are tightly controlled to ensure fertility and offspring viability. However, in many systems it has been shown that environmental factors can alter the frequency of crossover events. We have explored for the first time the effect of dietary changes on crossover frequency per nucleus. Our study was performed in spermatocytes of 3 mouse inbred strains by analyzing the number and position of crossovers along the synaptonemal complexes, as well as the length of such synaptonemal complexes, by immunostaining with antibodies against MLH1 (which allows the identification of the crossover sites) and SYCP3 (a component of the synaptonemal complex). Our results show that male recombination rate is sensitive to dietary changes, and this sensitivity depends on the genetic background in mice. This is first to report a nutrition effect on genome-wide levels of recombination.</p>