Colmonero-Costeira I, Guschanski K, Djaló S L, Fernandes N, Camará T, Farh K K-H, Kuderna L F K, Rogers J, Marques-Bonet T, Bruford M W, Russo I M, Jensen A, Ferreira da Silva M J
School of Biosciences, Cardiff University, Cardiff, Wales, UK.
CIBIO-Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Laboratório Associado, Universidade do Porto, Vairão, Portugal.
Mol Ecol. 2025 Jul 9:e17815. doi: 10.1111/mec.17815.
Understanding how small populations cope with loss of genetic diversity and deleterious variation is crucial to address the current biodiversity crisis. Insular populations are particularly interesting as they have often persisted at lower population sizes and higher inbreeding than their mainland counterparts. While the genome-wide consequences of inbreeding in threatened insular species have received some attention, comparative genomics between insular and mainland populations of widespread and genetically diverse species have rarely been performed. Yet, they are particularly well suited to inform about the consequences of drastic population declines from initially large populations-a phenomenon that is becoming increasingly common. The spot-nosed monkey (Cercopithecus petaurista), the Campbell's monkey (Cercopithecus campbelli) and the green monkey (Chlorocebus sabaeus) are common and genetically diverse West African primates. Insular populations can be found at the Bijagós Archipelago, Guinea-Bissau. Here, we assessed the genome-wide diversity, inbreeding, genetic load and adaptive variation using whole genome sequencing data from insular and mainland populations. In the three species, island populations showed lower genome-wide diversity and higher inbreeding. Genetic drift has likely promoted the conversion of masked genetic load into realised load without increased purging of deleterious variation. Additionally, we found no evidence for accumulation of deleterious variation, suggesting that these populations are not yet at risk of extinction by genetic factors and may act as reservoirs of extant mainland genetic diversity. We highlight, however, that other anthropogenic factors are threatening these insular primates, and therefore conservation management should target their immediate threats and safeguard against additional loss of diversity.
了解小种群如何应对遗传多样性丧失和有害变异对于应对当前的生物多样性危机至关重要。岛屿种群尤其令人感兴趣，因为它们往往在比大陆种群更低的种群规模和更高的近亲繁殖水平下存续。虽然受威胁岛屿物种近亲繁殖的全基因组后果已受到一些关注，但广泛分布且遗传多样的物种的岛屿种群和大陆种群之间的比较基因组学研究却很少进行。然而，它们特别适合用于了解从最初的大种群急剧下降的种群所带来的后果——这一现象正变得越来越普遍。斑鼻猴（Cercopithecus petaurista）、坎贝尔猴（Cercopithecus campbelli）和绿猴（Chlorocebus sabaeus）是常见且遗传多样的西非灵长类动物。在几内亚比绍的比热戈斯群岛可以找到它们的岛屿种群。在这里，我们使用来自岛屿种群和大陆种群的全基因组测序数据评估了全基因组多样性、近亲繁殖、遗传负荷和适应性变异。在这三个物种中，岛屿种群表现出较低的全基因组多样性和较高的近亲繁殖水平。遗传漂变可能促进了隐性遗传负荷向显性负荷的转化，而没有增加对有害变异的清除。此外，我们没有发现有害变异积累的证据，这表明这些种群尚未面临因遗传因素而灭绝的风险，并且可能作为现存大陆遗传多样性的储存库。然而，我们强调，其他人为因素正威胁着这些岛屿灵长类动物，因此保护管理应针对它们当前面临的威胁，并防止多样性的进一步丧失。
