Rockman Matthew V, Bernstein Max R, Çağlar Derin, Cattani M Victoria, Chang Audrey S, Kaur Taniya, Noble Luke M, Paaby Annalise B
Department of Biology and Center for Genomics & Systems Biology, New York University, New York, New York.
Woven Health Collective, New York, New York.
bioRxiv. 2025 Jun 7:2025.06.04.657873. doi: 10.1101/2025.06.04.657873.
Outbreeding populations harbor large numbers of recessive deleterious alleles that reduce the fitness of inbred individuals, and this inbreeding depression potentially shapes the evolution of mating systems, acting as a counterweight to the inherent selective advantage of self-fertilization. The population biological factors that influence inbreeding depression are numerous and often difficult to disentangle. We investigated the utility of obligately-outcrossing (gonochoristic) nematodes as models for inbreeding depression. By systematically inbreeding lines from ten populations and tracking line extinction, we found that inbreeding depression is universal but highly variable among species and populations. Inbreeding depression was detected across the life cycle, from mating to embryo production to embryonic viability and larval growth, and reciprocal crosses implicated female-biased effects. In most cases, the surviving inbred lines have dramatically reduced fitness, but the variance among inbred lines is substantial and compatible with the idea that inbreeding depression need not be an obstacle to the evolution of selfing in these worms. Populations of some species, including exhibited modest inbreeding depression and could be tractable laboratory models for gonochoristic .
远交种群中存在大量隐性有害等位基因，这些基因会降低近交个体的适应性，而这种近交衰退可能会影响交配系统的进化，成为自花受精固有选择优势的一种制衡力量。影响近交衰退的种群生物学因素众多，且往往难以厘清。我们研究了 obligately - outcrossing（雌雄异体）线虫作为近交衰退模型的实用性。通过系统地对来自十个种群的品系进行近交并追踪品系灭绝情况，我们发现近交衰退是普遍存在的，但在物种和种群之间差异很大。在从交配到胚胎产生、再到胚胎活力和幼虫生长的整个生命周期中都检测到了近交衰退，正反交表明存在雌性偏向效应。在大多数情况下，存活下来的近交品系适应性大幅降低，但近交品系之间的差异很大，这与近交衰退不一定是这些蠕虫自交进化障碍的观点相符。包括 在内的一些物种的种群表现出适度的近交衰退，可能是雌雄异体线虫易于处理的实验室模型。
