Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
School of Biological Sciences, University of Wollongong, Wollongong, New South Wales, Australia.
Mol Ecol. 2022 Dec;31(24):6605-6616. doi: 10.1111/mec.16723. Epub 2022 Oct 19.
Telomeres are nucleotide-protein caps, predominantly at the ends of Metazoan linear chromosomes, showing complex dynamics with regard to their lengthening and shortening through life. Their complexity has entertained the idea that net telomere length and attrition could be valuable biomarkers of phenotypic and genetic quality of their bearer. Intuitively, those individuals could be more heterozygous and, hence, less inbred. However, some inbred taxa have longer, not shorter, telomeres. To understand the role of inbreeding in this complex scenario we need large samples across a range of genotypes with known maternity and paternity in telomere-screened organisms under natural conditions. We assessed the effects of parental and hatchling inbreeding on telomere length in >1300 offspring from >500 sires and dams in a population of sand lizards (Lacerta agilis). Maternal and paternal ID and their interactions predict hatchling telomere length at substantial effect sizes (R > .50). Deviation from mean maternal heterozygosity statistically predicts shorter offspring telomeres but this only when sibship is controlled for by paternal ID, and then is still limited (R = .06). Raw maternal heterozygosity scores, ignoring absolute deviation from the mean, explained 0.07% of the variance in hatchling telomere length. In conclusion, inbreeding is not a driver of telomere dynamics in the sand lizard (Lacerta agilis) study system.
端粒是核苷酸-蛋白帽状结构，主要位于后生动物线性染色体的末端，其在生命过程中的延长和缩短呈现出复杂的动态变化。其复杂性引发了这样一种想法，即净端粒长度和损耗可能是其载体表型和遗传质量的有价值的生物标志物。直观地说，这些个体可能具有更高的杂合性，因此，它们的近交程度更低。然而，一些近交物种的端粒更长，而不是更短。为了理解近交在这种复杂情况下的作用，我们需要在自然条件下，在经过端粒筛选的生物体内，使用具有已知母性和父性的大量样本，跨越一系列基因型来进行研究。我们评估了亲代和孵化幼体的近交对沙蜥蜴（Lacerta agilis）超过 500 个亲体的超过 1300 个后代的端粒长度的影响。母性和父性 ID 及其相互作用以相当大的效应大小（R >.50）预测孵化幼体的端粒长度。从平均母性杂合度的偏差统计上预测到后代的端粒较短，但这仅在控制了父性 ID 的同胞关系时才适用，而且仍然有限（R =.06）。忽略从平均值的绝对偏差的原始母性杂合性评分解释了孵化幼体端粒长度的 0.07%的方差。总之，在沙蜥蜴（Lacerta agilis）研究系统中，近交不是端粒动力学的驱动因素。
