Sympatric speciation has been of key interest to biologists investigating how natural and sexual selection drive speciation without the confounding variable of geographic isolation. The advent of the genomic era has provided a more nuanced and quantitative understanding of the different and often complex modes of speciation by which sympatric sister taxa arose, and a reassessment of some of the most compelling empirical case studies of sympatric speciation. However, I argue that genomic studies based on contemporary populations may never be able to provide unequivocal evidence of true primary sympatric speciation, and there is a need to incorporate palaeogenomic studies into this field. This inability to robustly distinguish cases of primary and secondary ‘divergence with gene flow’ may be inconsequential, as both are useful for understanding the role of large effect barrier loci in the progression from localised genic isolation to genome-wide reproductive isolation. I argue that they can be of equivalent interest due to shared underlying mechanisms driving divergence and potentially leaving similar patterns of coalescence.

对于生物学家来说，研究自然和性别选择如何驱动物种形成而又不会造成地理隔离的混淆变量的问题，生物学家极为关注同伴形态形成。基因组时代的到来，对同胞姊妹类群的不同且通常是复杂的物种形成模式提供了更加细致入微的定量理解，并重新评估了一些最令人信服的同胞物种形成的经验案例研究。但是，我认为基于当代人群的基因组研究可能永远无法提供真正的主要同胞物种形成的明确证据，因此有必要将古基因组学纳入这一领域。这种无法可靠地区分主要和次要“基因流差异”的情况可能是无关紧要的，因为两者都有助于理解大效应屏障基因座在从局部基因分离到全基因组生殖分离过程中的作用。我认为，由于存在共同的基础机制，这些机制可以推动分歧并可能留下相似的合并模式，因此它们可能具有同等的意义。