Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123, Turin, Italy.
Mamm Genome. 2024 Mar;35(1):90-98. doi: 10.1007/s00335-023-10020-5. Epub 2023 Oct 21.
Inbreeding is a common phenomenon in small, fragmented or isolated populations, typical conditions of many threatened species. In the present paper, we used a new non-invasive approach based on the buccal micronucleus assay to evaluate the possible relationships between inbreeding and genomic damage using the dog as model species. In particular, we assessed the frequencies of micronuclei and other nuclear aberrations in a group of purebred dogs (n = 77), comparing the obtained data with those from a control group represented by mixed breed dogs (n = 75). We found a significant increase of micronuclei, nuclear buds and total nuclear aberrations frequencies in purebred dogs compared to mixed-bred dogs. The absence of significant differences in the frequency of micronuclei and other nuclear aberrations amongst different breeds reinforces the hypothesis that the observed increased genomic damage amongst purebred dogs may not be due to a different genomic instability typical of a particular breed, but to inbreeding itself. This hypothesis is further confirmed by the fact that other endogen confounding factors, such as sex, age and weight, do not contribute significantly to the increase of genomic damage observed amongst purebred dogs. In conclusion, results presented in this study showed that, in purebred dogs, inbreeding may increase the levels of genomic damage. Considering that genomic damage is associated with increased physiological problems affecting animal health, the results we obtained may represent a stimulus to discourage the use of intensive inbreeding practices in captive populations and to reduce the fragmentation of wild populations.
近亲繁殖是小、碎片化或孤立种群中的常见现象，是许多受威胁物种的典型条件。在本文中，我们使用了一种新的非侵入性方法，基于口腔微核试验，使用狗作为模型物种，评估近亲繁殖与基因组损伤之间的可能关系。特别是，我们评估了一组纯种狗（n=77）中微核和其他核异常的频率，将获得的数据与由杂种狗组成的对照组（n=75）的数据进行比较。与杂交狗相比，纯种狗的微核、核芽和总核异常频率显著增加。不同品种之间微核和其他核异常频率没有显著差异，这进一步证实了这样一种假设，即在纯种狗中观察到的增加的基因组损伤可能不是由于特定品种特有的不同基因组不稳定性，而是由于近亲繁殖本身。事实上，其他内源混杂因素，如性别、年龄和体重，对纯种狗中观察到的基因组损伤增加没有显著影响，这进一步证实了这一假设。总之，本研究的结果表明，在纯种狗中，近亲繁殖可能会增加基因组损伤的水平。考虑到基因组损伤与影响动物健康的生理问题增加有关，我们获得的结果可能会促使人们反对在圈养种群中使用密集的近亲繁殖实践，并减少野生种群的碎片化。
