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HYBRID ZONE ORIGINS, SPECIES BOUNDARIES, AND THE EVOLUTION OF WING‐PATTERN DIVERSITY IN A POLYTYPIC SPECIES COMPLEX OF NORTH AMERICAN ADMIRAL BUTTERFLIES (NYMPHALIDAE: LIMENITIS )
Author(s) -
Mullen Sean P.,
Dopman Erik B.,
Harrison Richard G.
Publication year - 2008
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2008.00366.x
Subject(s) - biology , coalescent theory , nymphalidae , gene flow , hybrid zone , evolutionary biology , mitochondrial dna , lineage (genetic) , subspecies , gene pool , nuclear gene , genetics , genetic variation , genetic diversity , gene , phylogenetics , zoology , population , ecology , butterfly , demography , sociology
Hybrid zones present opportunities to study the effects of gene flow, selection, and recombination in natural populations and, thus, provide insights into the genetic and phenotypic changes that occur early in speciation. Here we investigate a hybrid zone between mimetic ( Limenitis arthemis astyanax ) and nonmimetic ( Limenitis arthemis arthemis ) populations of admiral butterflies using DNA sequence variation from mtDNA and seven nuclear gene loci. We find three distinct mitochondrial clades within this complex, and observe a strong overall concordance between wing‐pattern phenotypes and mitochondrial variation. Nuclear gene genealogies, in contrast, revealed no evidence of exclusivity for either wing‐pattern phenotype, suggesting incomplete barriers to gene exchange and/or insufficient time for lineage sorting. Coalescent simulations indicate that gene flow between these two subspecies is highly asymmetric, with the majority of migration occurring from mimetic into nonmimetic populations. Selective sweeps of alleles responsible for mimetic phenotypes may have occurred more than once when mimetic and nonmimetic Limenitis occurred together in the presence of the model ( Battus philenor ).