Multiple paths to the same destination: Influence of gene flow on convergent evolution

Elucidation of the genetic mechanisms convergent evolution, evolution similar or same phenotypes in phylogenetically independent lineages, helps predict how populations will respond to selective pressures. Convergent can be caused by either fixation identical-by-descent alleles, mutations at gene, different genes controlling trait. To what extent does alleles lead isolated where inflow adaptive from other is limited? In a From Cover article this issue Molecular Ecology, Kemppainen et al. (2021) compared basis for reduction pelvic structures three freshwater nine-spined stickleback (Pungitius pungitius) Northern Europe. The authors used quantitative trait loci (QTL) mapping reveal that these was loci. contrast studies three-spined (Gasterosteus aculeatus), independently derived Pitx1 were shown responsible plate across multiple populations, found candidate causative gene only one population P. pungitius. This study highlights importance not presence flow but also its absence better understanding architecture evolution.