Relationship between effective population size, inbreeding and adult fitness-related traits in a steelhead (Oncorhynchus mykiss) population released in the wild

2013 ◽  
Vol 22 (5) ◽  
pp. 1295-1309 ◽  
Author(s):  
K. A. Naish ◽  
T. R. Seamons ◽  
M. B. Dauer ◽  
L. Hauser ◽  
T. P. Quinn
2010 ◽  
Vol 67 (9) ◽  
pp. 1449-1458 ◽  
Author(s):  
Donald M. Van Doornik ◽  
Barry A. Berejikian ◽  
Lance A. Campbell ◽  
Eric C. Volk

Conservation hatcheries, which supplement natural populations by removing adults or embryos from the natural environment and rearing and releasing parr, smolts, or adults back into their natal or ancestral streams, are increasingly being used to avoid extinction of localized populations of Pacific salmonids. We collected data before and during a steelhead ( Oncorhynchus mykiss ) supplementation program to investigate the effect that the program has had on the population’s genetic diversity and effective population size and any changes to an important life history trait (residency or anadromy). We found that supplementation did not cause substantial changes in the genetic diversity or effective size of the population, most likely because a large proportion of all of the steelhead redds in the river each year were sampled to create the supplementation broodstock. Our data also showed that the captively reared fish released as adults successfully produced parr. Furthermore, we found that during supplementation, there was an increase in the proportion of O. mykiss with anadromous ancestry vs. resident ancestry.


2011 ◽  
Vol 68 (8) ◽  
pp. 1369-1386 ◽  
Author(s):  
Amanda J. Finger ◽  
Eric C. Anderson ◽  
Molly R. Stephens ◽  
Bernard P. May

The threatened Paiute cutthroat trout ( Oncorhynchus clarkii seleniris , PCT) is endemic to Silver King Creek, California, USA, which was stocked with non-native trout beginning in 1930. Single nucleotide polymorphism (SNP) and microsatellite data reveal that the trout population in Silver King Creek is weakly structured and composed of introgressed California golden trout ( Oncorhynchus mykiss aguabonita , CAGT), hatchery rainbow trout ( Oncorhynchus mykiss , RT), and some native PCT. Two SNP groups were analyzed: (i) one mitochondrial and five autosomal SNPs, diagnostic between Lahontan cutthroat trout ( Oncorhynchus clarkii henshawi ) or PCT and CAGT or RT and (ii) one mitochondrial and five autosomal SNPs nearly diagnostic between CAGT and RT. The five autosomal cutthroat–rainbow SNPs were used to jointly estimate the cutthroat trout mixing proportion in Silver King Creek and effective population size (Ne) of the admixed population, using a coalescent-based maximum likelihood method. Given the stocking history of Silver King Creek, there are two different scenarios that bound the range of expected point estimates for Ne. We obtain point estimates of Ne = 150 and Ne = 750 for Silver King Creek under these two scenarios. This method will be useful in cases with differentiated taxa and in prioritizing conservation and restoration programs where the populations of concern are introgressed.


Genetics ◽  
1994 ◽  
Vol 136 (2) ◽  
pp. 685-692 ◽  
Author(s):  
Y X Fu

Abstract A new estimator of the essential parameter theta = 4Ne mu from DNA polymorphism data is developed under the neutral Wright-Fisher model without recombination and population subdivision, where Ne is the effective population size and mu is the mutation rate per locus per generation. The new estimator has a variance only slightly larger than the minimum variance of all possible unbiased estimators of the parameter and is substantially smaller than that of any existing estimator. The high efficiency of the new estimator is achieved by making full use of phylogenetic information in a sample of DNA sequences from a population. An example of estimating theta by the new method is presented using the mitochondrial sequences from an American Indian population.


Genetics ◽  
1997 ◽  
Vol 147 (4) ◽  
pp. 1977-1982
Author(s):  
Stephen T Sherry ◽  
Henry C Harpending ◽  
Mark A Batzer ◽  
Mark Stoneking

Abstract There are estimated to be ~1000 members of the Ya5 Alu subfamily of retroposons in humans. This Subfamily has a distribution restricted to humans, with a few copies in gorillas and chimpanzees. Fifty-seven Ya5 elements were previously cloned from a HeLaderived randomly sheared total genomic library, sequenced, and screened for polymorphism in a panel of 120 unrelated humans. Forty-four of the 57 cloned Alu repeats were monomorphic in the sample and 13 Alu repeats were dimorphic for insertion presence/absence. The observed distribution of sample frequencies of the 13 dimorphic elements is consistent with the theoretical expectation for elements ascertained in a single diploid cell line. Coalescence theory is used to compute expected total pedigree branch lengths for monomorphic and dimorphic elements, leading to an estimate of human effective population size of ~18,000 during the last one to two million years.


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