Genetic variants of RNF212 involved in meiotic recombination rate and its relation with conception rate in Japanese Black cattle

[INTRODUCTION] Reproduction is one of the most economically important traits of cattle production (Pinto De Melo et al. 2017). During recent decades, reproductive performance of cows as measured by conception rate (CR) in Japanese Black cattle has been gradually declining (Sato & Fujita 2010; Irikura et al. 2018). Various physiological and environmental factors could affect average CR of cattle. Of those, embryonic mortality are one of critical factors for CR and Diskin et al. (2012) estimated embryonic mortality of ～40% for dairy caw and direct effect of embryonic mortality are reflect on reduced CR. Therefore, to increase CR by reducing the embryonic mortality is an important matter for improving the reproductive performance of Japanese Black cattle. In human, a significant part of embryonic mortality is due to chromosomal abnormalities including aneuploidy and aneuploidy is known to be caused mainly by defects in the meiosis during oogenesis and spermatogenesis. In particular, the crossover, which formed between pared homologous chromosomes to physically connect the homologous chromosomes, is an important phenomenon to ensure proper chromosome segregation during meiosis and correct ploidy of the gametes (Bolcun-filas & Schimenti 2012; Ma et al. 2015).