Title

MHC-mediated local adaptation in reciprocally translocated Chinook salmon

Document Type

Article

Publication Date

2010

Publication Title

Conservation Genetics

Volume

11

Issue

6

First Page

2333

Last Page

2342

DOI

10.1007/s10592-010-0119-3

Keywords

Adaptive divergence; atlantic salmon; Balancing selection; chinook salmon; class-i; compatible-genes; cross-species amplification; Directional selection; genetic-variation; major histocompatibility complex; microsatellite loci; Nucleotide divergence; oncorhynchus-tshawytscha; pacific-northwest; selection; survival

Abstract

Most Pacific salmonid populations have faced significant population declines over the past 30 years. In order to effectively conserve and manage these populations, knowledge of the evolutionary adaptive state of individuals and the scale of adaptation across populations is needed. The vertebrate major histocompatibility complex (MHC) represents an important adaptation to parasites, and genes encoding for the MHC are widely held to be undergoing balancing selection. However, the generality of balancing selection across populations at MHC loci is not well documented. Using Chinook salmon (Oncorhynchus tshawytscha) from two populations, we follow the survival of full-sib family replicates reared in their natal river and reciprocally transplanted to a foreign river to examine selection and local adaptation at the MHC class I and II loci. In both populations, we found evidence of a survivorship advantage associated with nucleotide diversity at the MHC class I locus. In contrast, we found evidence that MHC class II diversity was disadvantageous in one population. There was no evidence that these effects occurred in translocated families, suggesting some degree of local adaptation at the MHC loci. Thus, our results implicate balancing selection at the MHC class I but potentially differing selection across populations at the class II locus.

Comments

This is an accepted manuscript version of an aritcle whose version of record was published in:Conservation Genetics: http://dx.doi.org/10.1007/s10592-010-0119-3