Frequent paternal mitochondrial inheritance and rapid haplotype frequency shifts in copepod hybrids

Mitochondria are assumed to be maternally inherited in most animal species, and this foundational concept has fostered advances in phylogenetics, conservation, and population genetics. Like other animals, mitochondria were thought to be solely maternally inherited in the marine copepod Tigriopus californicus, which has served as a useful model for studying mitonuclear interactions, hybrid breakdown, and environmental tolerance. However, we present PCR, Sanger sequencing, and Illumina Nextera sequencing evidence that extensive paternal mitochondrial DNA (mtDNA) transmission is occurring in inter-population hybrids of T. californicus. PCR on four types of crosses between three populations (total sample size of 376 F1 individuals) with 20% genome-wide mitochondrial divergence showed 2% to 59% of F1 hybrids with both paternal and maternal mtDNA, where low and high paternal leakage values were found in different cross directions of the same population pairs. Sequencing methods further verifi...绝大多数动物物种的线粒体被认为遵循母系遗传模式，这一基础性概念推动了系统发育学、保护生物学与群体遗传学领域的研究进展。作为研究核质互作、杂交衰退及环境耐受性的经典模式生物，海洋桡足类加州虎斑猛水蚤（Tigriopus californicus）此前也被认为仅存在母系线粒体遗传。然而本研究通过聚合酶链式反应（PCR）、桑格测序（Sanger sequencing）及Illumina Nextera测序的实验证据证实，加州虎斑猛水蚤的种群间杂交后代中存在广泛的父系线粒体DNA（mtDNA）传递现象。本研究对3个全基因组线粒体分化度达20%的种群间的4种杂交组合（总计376个F1个体）开展PCR检测，结果显示2%至59%的F1杂交后代同时携带父系与母系mtDNA；同一种群对的不同杂交方向中，父系渗漏率差异显著，最低为2%、最高达59%。测序技术进一步验证了