Fitness dynamics within a poplar hybrid zone: I. Prezygotic and postzygotic barriers impacting a native poplar hybrid stand

Ecology and Evolution

Amanda D. Roe¹  Chris J. K. MacQuarrie²  Marie-Claude Gros-Louis¹  J. Dale Simpson³  Josyanne Lamarche¹  Tannis Beardmore³  Stacey L. Thompson¹  Philippe Tanguay¹ 

[1] Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Québec, Québec, Canada;Natural Resources Canada, Canadian Forestry Centre, Great Lakes Forestry Centre, Sault Ste. Marie, Ontario, Canada;Natural Resources Canada, Canadian Forest Service, Atlantic Forestry Centre, Fredericton, New Brunswick, Canada

关键词: Hybrid fitness;    hybridization;    introgression;    postzygotic fitness;    reproductive fitness;    SNPs;   

DOI  :  10.1002/ece3.1029

来源: Wiley

【 摘 要 】

Abstract

Hybridization and introgression are pervasive evolutionary phenomena that provide insight into the selective forces that maintain species boundaries, permit gene flow, and control the direction of evolutionary change. Poplar trees (Populus L.) are well known for their ability to form viable hybrids and maintain their distinct species boundaries despite this interspecific gene flow. We sought to quantify the hybridization dynamics and postzygotic fitness within a hybrid stand of balsam poplar (Populus balsamifera L.), eastern cottonwood (P. deltoides Marsh.), and their natural hybrids to gain insight into the barriers maintaining this stable hybrid zone. We observed asymmetrical hybrid formation with P. deltoides acting as the seed parent, but with subsequent introgression biased toward P. balsamifera. Native hybrids expressed fitness traits intermediate to the parental species and were not universally unfit. That said, native hybrid seedlings were absent from the seedling population, which may indicate additional selective pressures controlling their recruitment. It is imperative that we understand the selective forces maintaining this native hybrid zone in order to quantify the impact of exotic poplar hybrids on this native system.

【 授权许可】

CC BY   
© 2014 Natural Resources Canada. Ecology and Evolution published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.