Data from: Ancestry-specific methylation patterns in admixed offspring from an experimental coyote and gray wolf cross

Reduced fitness of admixed individuals is typically attributed to genetic incompatibilities. Although mismatched genomes can lead to fitness changes, in some cases the reduction in hybrid fitness is subtle. The potential role of transcriptional regulation in admixed genomes could provide a mechanistic explanation for these discrepancies, but evidence is lacking for non-model organisms.Here, we explored the intersection of genetics and gene regulation in admixed genomes derived from an experimental cross between a western gray wolf and western coyote. We found a significant positive association between methylation and wolf ancestry, and identified outlier genes that have been previously implicated in inbreeding-related, or otherwise deleterious, phenotypes. We describe a pattern of site-specific, rather than genome-wide, methylation driven by inter-specific hybridization. Epigenetic variation is thus suggested to play a non-trivial role in both maintaining and combating mismatched genotypes through putative transcriptional mechanisms. We conclude that the regulation of gene expression is an underappreciated key component of hybrid genome functioning, but could also act as a potential source of novel and beneficial adaptive variation in hybrid offspring.

杂交个体的适合度降低通常被归因于遗传不相容性。尽管基因组不匹配可引发适合度改变，但在部分情境中，杂交适合度的降低并不显著。转录调控在杂交基因组中的潜在作用，或可为这类差异提供机制层面的解释，但目前非模式生物相关的研究证据仍较为匮乏。本研究针对西部灰狼（western gray wolf）与西部郊狼（western coyote）的实验杂交后代所构建的杂交基因组，探究了遗传学与基因调控之间的交叉关联。研究发现，甲基化（methylation）水平与灰狼血统占比存在显著正相关关系，并鉴定出一批此前被证实与近交相关或存在有害表型的异常基因（outlier genes）。本研究揭示了由种间杂交介导的位点特异性甲基化模式，而非全基因组范围的甲基化改变。由此表明，表观遗传变异可通过潜在的转录调控机制，在维持与对抗不匹配基因型两方面发挥不容忽视的作用。本研究得出结论：基因表达调控是杂交基因组功能中长期被忽视的关键组成部分，同时也可能成为杂交后代产生新颖有益适应性变异的潜在来源。