Rapid establishment of species barriers in plants compared to animals

Speciation, the process by which new reproductively isolated species arise from ancestral populations, occurs because of genetic changes that accumulate over time. To date, the notion that interspecific genetic exchange occurs more frequently between plant species than animals species has gained a strong footing in the scientific discourse, albeit primarily relying on verbal arguments centered on mating behavior. By examining the dynamics of gene flow across a continuum of divergence in both kingdoms, we observe the opposite relationship: plants experience less introgression than animals at the same level of genetic divergence, suggesting that species barriers are established more rapidly in plants. This pattern questions the differences in microevolutionary processes between plants and animals that impact genetic exchange at the macroevolutionary scale. One Sentence Summary Genetic exchange is more frequent between animal species than plants, challenging historical views. ### Competing Interest Statement The authors have declared no competing interest.