Non-additive genetic effects induce novel phenotypic distributions in male mating traits of F1 hybrids

Hybridization is a source of phenotypic novelty and variation because of
increased additive genetic variation. Yet, the roles of non-additive
allelic interactions in shaping phenotypic mean and variance of hybrids
have been underappreciated. Here we examine the distributions of
male-mating traits in F1 hybrids via a meta-analysis of 3,208 effect sizes
from 39 animal species pairs. Although additivity sets phenotypic
distributions of F1s to be intermediate, F1s also showed recessivity and
resemblance to maternal species. F1s expressed novel phenotypes (beyond
the range of both parents) in 65% of species pairs, often associated with
increased phenotypic variability. Overall, however, F1s expressed smaller
variation than parents in 51% of traits. While genetic divergence between
parents did not impact phenotypic novelty, it increased phenotypic
variability of F1s. By creating novel phenotypes with increased
variability, non-additivity of heterozygotic genome may play key roles in
determining mating success of F1s, and their subsequent extinction or
speciation.