Ballou J D
Department of Zoological Research, National Zoological Park, Smithsonian Institution, Washington, D.C. 20008, USA.
J Hered. 1997 May-Jun;88(3):169-78. doi: 10.1093/oxfordjournals.jhered.a023085.
Inbreeding depression can be reduced, or purged, by selection against deleterious alleles. This prediction is the basis of the recommendation that captive wildlife populations suffering from inbreeding depression be intentionally bred from healthy inbred animals. Yet data on the effectiveness of purging inbreeding depression are few. In this study I present and use two different regression models (an ancestral inbreeding model and a lethal recessive model) to test for the presence of purging effects in 25 captive mammalian populations. Fitness components examined were neonatal survival, survival from neonate to weaning, and litter size. In only one species was purging statistically significant. However, 15 of 17 species that showed inbreeding depression exhibited a slight decline in inbreeding depression in neonatal survival among descendants of inbred animals. These results show a small but highly significant trend of purging on neonatal survival. No trends in purging effects were observed in weaning survival or litter size. The effects were not likely to be strong enough to be of practical use in eliminating inbreeding depression.
近亲繁殖衰退可以通过对有害等位基因的选择来减少或消除。这一预测是建议的基础，即患有近亲繁殖衰退的圈养野生动物种群应故意从健康的近交动物中繁殖后代。然而，关于消除近亲繁殖衰退有效性的数据很少。在本研究中，我提出并使用了两种不同的回归模型（祖先近亲繁殖模型和致死隐性模型）来测试25个圈养哺乳动物种群中是否存在消除效应。所检查的适合度成分包括新生幼崽存活率、从新生到断奶的存活率以及窝仔数。只有一个物种的消除效应在统计学上具有显著性。然而，在表现出近亲繁殖衰退的17个物种中，有15个物种在近交动物后代的新生幼崽存活率方面，近亲繁殖衰退略有下降。这些结果显示出在新生幼崽存活率上存在一个虽小但高度显著的消除趋势。在断奶存活率或窝仔数方面未观察到消除效应的趋势。这些效应可能不够强大，无法在消除近亲繁殖衰退方面实际应用。
