Reduced heterozygosity depresses sperm quality in wild rabbits, Oryctolagus cuniculus
Reduced heterozygosity depresses sperm quality in wild rabbits, Oryctolagus cuniculus
复制标题
DOI：
10.1016/j.cub.2006.02.059
复制
发表时间：
2006-03-21
期刊：
影响因子：
9.2
通讯作者：
Hewitt, GM
中科院分区：
文献类型：
--
作者：
Gage, MJG;Surridge, AK;Hewitt, GM
当近亲被迫繁殖时，所产生的后代遗传了高于平均水平的纯合性和降低的适应性[1，2]。生物学家现在认识到野生环境中的近亲繁殖衰退[3-5]，随着自然种群的枯竭和破碎，这种现象可能会增加。近交衰退最常见的表现为生育力和胚胎发育受损[4]，但实际机制仍然知之甚少，特别是对于野生种群。在这里，我们研究了杂合性降低如何影响在英国各地采样的野兔（Oryctolagus cuniculus）的精子和性腺特征。通过使用一套29个微卫星标记（分析以确认我们样本中个体杂合性的代表性），我们发现杂合性与正常精子的产生之间存在显着的负相关关系;这种关系在（n = 12）和（n = 91 [总男性]，42 [岛屿]，49 [大陆]）人群之间都显着。杂合性降低也与男性睾丸大小减少有关（n = 112），但在人群水平上没有发现相关性，表明环境混淆。我们的研究结果表明，对于野生哺乳动物，近亲繁殖与精子质量下降有关，证实了近亲繁殖与罕见猫科动物精子异常升高之间的联系[6-8]。这些发现可以解释为什么近交衰退如此频繁地通过受损的生育力和胚胎发生而出现[4]。
When close relatives are forced to reproduce, the resulting offspring inherit above average homozygosity and reduced fitness [1, 2]. Biologists now recognize inbreeding depression in the wild [3-5], a phenomenon that will probably increase as natural populations become depleted and fragmented. Inbreeding depression is most commonly expressed as compromised fertility and embryogenesis [4], but actual mechanisms remain poorly understood, especially for wild populations. Here, we examine how reduced heterozygosity influences spermatozoal and gonadal traits in wild rabbits (Oryctolagus cuniculus) sampled across the United Kingdom. By using a suite of 29 microsatellite markers (analyzed to confirm representation of individual heterozygosity across our sample), we found a significant negative relationship between heterozygosity and the production of normal sperm; the relationship was significant both between (n = 12) and within (n = 91 [total males], 42 [island], 49 [mainland]) populations. Reduced heterozygosity was also associated with decreased testis size across males (n = 112), but no relationship was seen at the population level, suggesting environmental confounds. Our results show, for a wild mammal, that inbreeding is associated with decreased sperm quality, confirming suggestions of links between inbreeding and elevated sperm abnormalities in rare felids [6-8]. These findings could explain why inbreeding depression so frequently arises via compromised fertility and embryogenesis [4].