Open AccessMorphometry of two cryptic tree frog species at their hybrid zone reveals neither intermediate nor transgressive morphotypes
Author(s) -
Majtyka Tomasz,
Borczyk Bartosz,
Ogielska Maria,
Stöck Matthias
Publication year - 2022
Publication title -
ecology and evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.17
H-Index - 63
ISSN - 2045-7758
DOI - 10.1002/ece3.8527
Subject(s) - biology , transgressive segregation , transgressive , allopatric speciation , hybrid , evolutionary biology , hybrid zone , reproductive isolation , morphometrics , species complex , tree frog , phenotypic trait , zoology , ecology , gene flow , phenotype , genetics , gene , phylogenetic tree , genetic variation , quantitative trait locus , botany , sedimentary depositional environment , paleontology , population , demography , structural basin , sociology
Abstract Under incomplete reproductive isolation, secondary contact of diverged allopatric lineages may lead to the formation of hybrid zones that allow to study recombinants over several generations as excellent systems of genomic interactions resulting from the evolutionary forces acting on certain genes and phenotypes. Hybrid phenotypes may either exhibit intermediacy or, alternatively, transgressive traits, which exceed the extremes of their parents due to epistasis and segregation of complementary alleles. While transgressive morphotypes have been examined in fish, reptiles, birds, and mammals, studies in amphibians are rare. Here, we associate microsatellite‐based genotypes with morphometrics‐based morphotypes of two tree frog species of the Hyla arborea group, sampled across a hybrid zone in Poland, to understand whether the genetically differentiated parental species also differ in morphology between each other and their hybrids and whether secondary contact leads to the evolution of intermediate or transgressive morphotypes. Using univariate approaches, explorative multivariate methods (principal component analyses) as well as techniques with prior grouping (discriminant function analyses), we find that morphotypes of both parental species and hybrids differ from each other. Importantly, hybrid morphotypes are neither intermediate nor transgressive but found to be more similar to H . orientalis than to H . arborea .