PSV-11 A comparison of meiotic recombination in spermatocytes of cattle and sheep from the United States and Czech Republic.

摘要

Understanding meiotic recombination is valuable for learning how traits are inherited in livestock. Homologous recombination is an important component of gametogenesis that contributes to genetic variation and ensures proper chromosome segregation. Despite the importance of this process, little is known about the factors that control and/or influence global meiotic recombination/crossover (CO) in livestock. Previous research recognizes that a least one CO per chromosome arm is required to ensure proper chromosome segregation. Even though cattle and sheep are different species, they have the same number of chromosome arms. This study uses a direct cytological approach to quantify and characterize the number of COs in spermatocytes from U.S. Angus and Czech Spotted cattle, and diverse breeds of sheep from the United States and Czech Republic. Here we report that Angus exhibit on average 43.1 COs per spermatocyte, which are significantly fewer than 47.5 in Czech spotted cattle. US sheep in this study (Suffolk = 61.1, Icelandic = 63.5, and Targhee = 65.9), on average exhibit 62.5 COs per spermatocyte, which is similar to 62.9 observed in Czech sheep. Cattle have more than the one required CO per chromosome arm. Interestingly, sheep have approximately 28% more COs per spermatocyte than cattle. Further, we examined the number and location of COs for each homologous chromosome pair in a subset of cattle and sheep spermatocytes to better understand regions and frequency of the COs on individual chromosomes. Overall, this research contributes valuable information towards understanding meiotic recombination, and ultimately how traits are inherited in livestock.