Germplasm and Reproductive Technology Laboratory, Department of Animal Production & Technology, Chinhoyi University of Technology, Chinhoyi, Zimbabwe.
Department of Biotechnology and Biochemistry, University of Zimbabwe, Harare, Zimbabwe.
Reprod Domest Anim. 2021 Oct;56(10):1293-1301. doi: 10.1111/rda.13991. Epub 2021 Aug 5.
Conservation decisions based on neutral genetic diversity have been observed to promote retention of useful quantitative variation in biological populations. An experiment was undertaken to determine the association between microsatellite marker polymorphisms and phenotypic variation in semen production and cryosurvival traits in bulls. Thirty-five ejaculates were collected from ten bulls of two breeds and evaluated before and after cryopreservation for several semen traits. The bulls were also genotyped using a set of sixteen bovine-specific microsatellite marker loci. Fixation indices (F ), heterozygosity and Nei's genetic distance measures were computed from allele frequency data for each of the bulls. Molecular and phenotypic data were used to compute tri-distance matrices for the ten bulls and correlated using Mantel's test in GenAIEx 6.5. The study revealed extensive heterogeneity in semen traits, heterozygosity and F values among the bulls. Large pairwise phenotypic and genetic distances were also observed. Correlation between pairwise genetic distances and phenotypic distances was significant and highly positive for sperm viability (r = .61, p < .001) and moderately positive for sperm motility (r = .40-42, p < .05) variables. For sperm morphology, ejaculate volume and sperm concentration, correlation with genetic distances was positive, low and not significantly different from zero (p > .05). A tendency for a triangular-shaped relationship between genetic and phenotypic distances for post-thaw motility and viability traits was also observed. Accordingly, association with neutral genetic diversity was absent for semen production traits and moderate to highly positive for sperm cryosurvival traits. Given these findings, conservation decisions based on neutral genetic diversity may capture variation in some adaptive traits, but not others.
基于中性遗传多样性的保护决策已被观察到可促进生物种群中有用的数量变异的保留。进行了一项实验，以确定微卫星标记多态性与精液生产和冷冻保存后存活特性的表型变异之间的关联。从两个品种的十头公牛中采集了 35 个精液样本，在冷冻保存前后对其进行了几个精液特性的评估。还使用一组 16 个牛特异性微卫星标记基因座对公牛进行了基因分型。从每个公牛的等位基因频率数据计算了固定指数 (F)、杂合度和 Nei 的遗传距离度量。分子和表型数据用于计算十个公牛的三距离矩阵，并在 GenAIEx 6.5 中使用 Mantel 检验进行相关性分析。该研究揭示了公牛之间精液特性、杂合度和 F 值的广泛异质性。还观察到大量的成对表型和遗传距离。成对遗传距离与表型距离之间的相关性对于精子活力 (r =.61, p <.001) 和精子运动性 (r =.40-42, p <.05) 变量显著且高度正相关。对于精子形态、精液量和精子浓度，与遗传距离的相关性为正、低且与零无显著差异 (p >.05)。还观察到解冻后运动和活力特性的遗传和表型距离之间存在三角形关系的趋势。因此，基于中性遗传多样性的保护决策可能会捕获一些适应性特征的变异，但不是其他特征的变异。
