What occurs during speciation reversal?

Speciation reversal refers to the process where previously distinct species merge and interbreed, leading to a situation where the genetic boundaries that defined these species blur. This can happen due to various factors, such as changes in the environment, loss of barriers that separated the species, or demographics that promote contact between the two groups. When these species interbreed, their gene pools may mix, which can reintroduce genetic variation and lead to the formation of hybrid organisms.

This process contrasts with speciation, where two populations diverge to become separate species due to different evolutionary pressures or geographic separation. In speciation reversal, instead of becoming more distinct, the genetic lines between populations become less defined, resulting in hybrids that may exhibit traits from both parent species. This phenomenon can challenge the traditional concepts of species and highlight the fluidity of evolutionary processes.