Premium
DISCORDANT DIVERGENCE TIMES AMONG Z‐CHROMOSOME REGIONS BETWEEN TWO ECOLOGICALLY DISTINCT SWALLOWTAIL BUTTERFLY SPECIES
Author(s) -
Putnam Andrea S.,
Scriber J. Mark,
Andolfatto Peter
Publication year - 2007
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.1558-5646.2007.00076.x
Subject(s) - biology , coalescent theory , allopatric speciation , introgression , reproductive isolation , evolutionary biology , gene flow , genetic algorithm , hybrid zone , divergence (linguistics) , chromosome , ecology , genetics , gene , phylogenetics , genetic variation , population , linguistics , philosophy , demography , sociology
We investigate multilocus patterns of differentiation between parental populations of two swallowtail butterfly species that differ at a number of ecologically important sex‐linked traits. Using a new coalescent‐based approach, we show that there is significant heterogeneity in estimated divergence times among five Z‐linked markers, rejecting a purely allopatric speciation model. We infer that the Z chromosome is a mosaic of regions that differ in the extent of historical gene flow, potentially due to isolating barriers that prevent the introgression of species‐specific traits that result in hybrid incompatibilities. Surprisingly, a candidate region for a strong barrier to introgression, Ldh , does not show a significantly deeper divergence time than other markers on the Z chromosome. Our approach can be used to test alternative models of speciation and can potentially assign chronological order to the appearance of factors contributing to reproductive isolation between species.