Abstract

Genome evolution is predicted to be rapid following the establishment of new (neo) sex chromosomes, but it is not known if neo-sex chromosome evolution plays an important role in speciation. Here we combine extensive crossing experiments with population and functional genomic data to examine neo-XY chromosome evolution and incipient speciation in the mountain pine beetle. We find a broad continuum of intrinsic incompatibilities in hybrid males that increase in strength with geographic distance between reproductively isolated populations. This striking progression of reproductive isolation is coupled with extensive gene specialization, natural selection, and elevated genetic differentiation on both sex chromosomes. Closely related populations isolated by hybrid male sterility also show fixation of alternative neo-Y haplotypes that differ in structure and male-specific gene content. Our results suggest that neo-sex chromosome evolution can drive rapid functional divergence between closely related populations irrespective of ecological drivers of divergence.

Details

Title
Rapid neo-sex chromosome evolution and incipient speciation in a major forest pest
Author
Bracewell, Ryan R 1 ; Bentz, Barbara J 2 ; Sullivan, Brian T 3 ; Good, Jeffrey M 4 

 Department of Ecosystem and Conservation Sciences, The University of Montana, Missoula, MT, USA; Department of Integrative Biology, University of California, Berkeley, CA, USA 
 USDA Forest Service Rocky Mountain Research Station, Logan, UT, USA 
 USDA Forest Service Southern Research Station, Pineville, LA, USA 
 Division of Biological Sciences, The University of Montana, Missoula, MT, USA 
Pages
1-14
Publication year
2017
Publication date
Nov 2017
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1983433216
Copyright
© 2017. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.