Shen Botong, Freebern Ellen, Jiang Jicai, Maltecca Christian, Cole John B, Liu George E, Ma Li
Department of Animal and Avian Sciences, University of Maryland, College Park, College Park, MD, United States.
Department of Animal Science, North Carolina State University, Raleigh, NC, United States.
Front Genet. 2021 Jul 20;12:682718. doi: 10.3389/fgene.2021.682718. eCollection 2021.
Meiotic recombination is a fundamental biological process that facilitates meiotic division and promotes genetic diversity. Recombination is phenotypically plastic and affected by both intrinsic and extrinsic factors. The effect of maternal age on recombination rates has been characterized in a wide range of species, but the effect's direction remains inconclusive. Additionally, the characterization of temperature effects on recombination has been limited to model organisms. Here we seek to comprehensively determine the impact of genetic and environmental factors on recombination rate in dairy cattle. Using a large cattle pedigree, we identified maternal recombination events within 305,545 three-generation families. By comparing recombination rate between parents of different ages, we found a quadratic trend between maternal age and recombination rate in cattle. In contrast to either an increasing or decreasing trend in humans, cattle recombination rate decreased with maternal age until 65 months and then increased afterward. Combining recombination data with temperature information from public databases, we found a positive correlation between environmental temperature during fetal development of offspring and recombination rate in female parents. Finally, we fitted a full recombination rate model on all related factors, including genetics, maternal age, and environmental temperatures. Based on the final model, we confirmed the effect of maternal age and environmental temperature during fetal development of offspring on recombination rate with an estimated heritability of 10% ( = 0.03) in cattle. Collectively, we characterized the maternal age and temperature effects on recombination rate and suggested the adaptation of meiotic recombination to environmental stimuli in cattle. Our results provided first-hand information regarding the plastic nature of meiotic recombination in a mammalian species.
减数分裂重组是一个基本的生物学过程，它促进减数分裂并增加遗传多样性。重组在表型上具有可塑性，受内在和外在因素的影响。母体年龄对重组率的影响已在多种物种中得到表征，但其影响方向仍无定论。此外，温度对重组影响的表征仅限于模式生物。在这里，我们试图全面确定遗传和环境因素对奶牛重组率的影响。利用一个大型牛谱系，我们在305,545个三代家庭中确定了母体重组事件。通过比较不同年龄父母的重组率，我们发现牛的母体年龄与重组率之间呈二次趋势。与人类中增加或减少的趋势不同，牛的重组率随着母体年龄的增加而下降，直到65个月，然后上升。将重组数据与来自公共数据库的温度信息相结合，我们发现后代胎儿发育期间的环境温度与母本的重组率之间存在正相关。最后，我们根据所有相关因素拟合了一个完整的重组率模型，包括遗传学、母体年龄和环境温度。基于最终模型，我们证实了后代胎儿发育期间母体年龄和环境温度对重组率的影响，在牛中估计遗传力为10%（=0.03）。总体而言，我们表征了母体年龄和温度对重组率的影响，并表明牛的减数分裂重组对环境刺激的适应性。我们的结果提供了关于哺乳动物物种减数分裂重组可塑性本质的第一手信息。
