Go to  Advanced Search

Investigating the divergence of reproductive ecotypes in Kokanee salmon

Show simple item record

dc.contributor.author Frazer, Karen Kiyomi
dc.date.accessioned 2012-07-31T16:56:02Z
dc.date.available 2012-07-31T16:56:02Z
dc.date.copyright 2012 en_US
dc.date.issued 2012-07-31
dc.identifier.uri http://hdl.handle.net/2429/42839
dc.description.abstract Investigating the role of natural selection in driving adaptive diversification has become a central theme in evolutionary ecology as advancements in genome typing technologies provide new approaches for identifying the genetic basis of phenotypic diversity in non-model organisms. I used population-based genome scans to investigate the recent divergence of shore- and stream-spawning ecotypes in Kokanee salmon (Oncorhynchus nerka). These ecotypes co-exist in many post-glacial lakes throughout their range, and exhibit distinct reproductive behaviors, spawning habitat preference, and life history traits. Several algorithms were used to test for statistical outliers across five replicate ecotype pairs of Kokanee salmon. Among 50 expressed sequence tag (EST)-linked and anonymous microsatellite loci, signatures of directional selection were observed at 15 loci, including four loci that exhibited outlier behaviour across two or more lakes. The inconsistency of parallel patterns suggests that either several different genes or genetic pathways underlie ecotype divergence or outlier-detection methods are prone to Type II error when selection is weak. Nonetheless, population structure and differentiation at outlier loci is distinct from that of neutral loci, which infers that outliers may be under selection. Annotations of EST-linked outliers suggest that energy metabolism and pathogen resistance may be involved in initiating and maintaining barriers to gene flow between these two reproductive ecotypes. Within a Kokanee fisheries management context, markers associated with adaptive genetic variation would be very useful since neutral microsatellite markers cannot distinguish these recently diverged ecotypes (<10,000 years). Currently, the absolute abundance of shore-spawning Kokanee cannot be determined using conventional methods and ecotypes cannot be determined for angled fish to estimate ecotype-specific harvest rates. Here, I assess the accuracy and power of outlier loci in distinguishing shore- and stream-spawning Kokanee using mixed stock analyses and individual assignment tests. In general, outlier loci outperform neutral loci and simulations suggest that management-relevant levels of accuracy (>90%) may be achieved with sufficient baseline sampling and ecotype differentiation. Thus, genome scans can be useful in identifying informative markers for recently diverged stocks. en_US
dc.language.iso eng en_US
dc.publisher University of British Columbia en
dc.title Investigating the divergence of reproductive ecotypes in Kokanee salmon en_US
dc.type Electronic Thesis or Dissertation en
dc.degree.name Master of Science - MSc en_US
dc.degree.discipline Biology en_US
dc.degree.grantor University of British Columbia en
dc.date.graduation 2012-11 en_US
dc.degree.campus UBCO en_US
dc.description.scholarlevel Graduate en


Files in this item

Files Size Format Description   View
ubc_2012_fall_frazer_karen.pdf 4.994Mb Adobe Portable Document Format   View/Open
 

This item appears in the following Collection(s)

Show simple item record

All items in cIRcle are protected by copyright, with all rights reserved.

UBC Library
1961 East Mall
Vancouver, B.C.
Canada V6T 1Z1
Tel: 604-822-6375
Fax: 604-822-3893