Journal
AMERICAN NATURALIST
Volume 192, Issue 5, Pages E178-E188Publisher
UNIV CHICAGO PRESS
DOI: 10.1086/699162
Keywords
hybridization; hybrid zones; Haldane's rule; large X-effect; reproductive isolation; speciation
Categories
Funding
- Heisenberg Fellowship [Sto 493/2-1, 2-2]
- German Science Foundation (DFG) [Sto 493/3-1]
- Swiss National Science Foundation [P2LAP3_171818]
- Swiss National Science Foundation (SNF) [P2LAP3_171818] Funding Source: Swiss National Science Foundation (SNF)
Ask authors/readers for more resources
Divergence between incipient species remains an incompletely understood process. Hybrid zones provide great research potential, reflecting natural organismal genomic interactions and gene evolution in a variety of recombinants over generations. While sex chromosomes are known evolutionary drivers of reproductive isolation, empirical population genetics has mostly examined species with heteromorphic sex chromosomes. We recently reported restricted introgression at sex-linked markers in an amphibian system with homomorphic sex chromosomes (Hyla), consistent with a large X-effect, designating a greater role of sex chromosomes in driving hybrid incompatibilities. Here, using a similar approach, we examined two hybrid zones of Palearctic green toads (Bufo viridis subgroup), involving several lineages that arose at different times and form secondary contacts. We find no evidence for differential introgression of sex-linked versus autosomal markers across both zones. This absence of large X-effects in Bufo indicates that, unlike in Hyla, hybrid incompatibilities may not result from the faster-heterogametic sex and faster-male aspects of Haldane's rule. The recent suppression of XY recombination in Hyla but not in Bufo may have driven greater divergence between Hyla sex chromosomes, causing stronger reproductive isolation. Alternatively, stronger linkage among Hyla's sex-linked markers could restrict introgression. We hypothesize that the degree of sex-specific recombination may condition the importance of homomorphic sex chromosomes in speciation.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available