Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8790
Title: Effective number of breeders from sibship reconstruction: empirical evaluations using hatchery steelhead
Author: M. W. Ackerman, Brian K. Hand, Ryan K. Waples, G. Luikart, Robin S. Waples, C. Steele, B. Garner, J. McCane, Matthew A. Campbell
Publication Year: 2016
Journal: Evolutionary Applications

Effective population size (NE) is among the most important metrics in evolutionary biology. In natural populations, it is often difficult to collect adequate demographic data to calculate NE directly. Consequently, genetic methods to estimate NE have been developed. Two NE estimators based on sibship reconstruction using multi-locus genotype data have been developed in recent years; sibship assignment and parentage analysis without parents. In this study, we evaluated the accuracy of sibship reconstruction using a large empirical dataset from five hatchery steelhead populations with known pedigrees and using 95 SNPs. We challenged the software COLONY with 2,599,961 known relationships and demonstrated that reconstruction of full-sib and unrelated pairs were greater than 95% and 99% accurate, respectively; however, reconstruction of half-sib pairs was poor (< 5% accurate). Despite poor half-sib reconstruction, both estimators provided accurate estimates of Nb when sample sizes were near or greater than the true Nb and when assuming a monogamous mating system. We further demonstrated that both methods provide roughly equivalent estimates of Nb. Our results indicate that sibship reconstruction and current SNP panels provide promise for estimating Nb in steelhead populations in the region.

Theme: Recovery and rebuilding of marine and coastal species
Foci: Characterize the population biology of species, and develop and improve methods for predicting the status of populations.
Evaluate the effects of artificial propagation on recovery, rebuilding and sustainability of marine and anadromous species.
Official Citation:

Ackerman, MW, BK Hand, RK Waples, G Luikart, RS Waples, C Steele, BA Garner, J McCane, and M Campbell.  2017.  Effective number of breeders from sibship reconstruction: empirical evaluations using hatchery steelhead.  Evolutionary Applications 10:146-160 (DOI: 10.1111/eva.12433.)