Seafood Cooperative Research Center

Adelaide, Australia

Seafood Cooperative Research Center

Adelaide, Australia

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Miller P.A.,University of Tasmania | Miller P.A.,Seafood Cooperative Research Center | Elliott N.G.,CSIRO | Vaillancourt R.E.,University of Tasmania | And 2 more authors.
Aquaculture | Year: 2014

Tetraploid Pacific oysters (Crassostrea gigas) are commonly used within aquaculture to generate predominantly sterile triploids for commercial use. Unlike triploids, tetraploids are fertile and can be spawned with each other to maintain a commercial breeding population. The impacts this hatchery perpetuation has on the genetic diversity of the tetraploid population and subsequent commercial triploid product are currently unknown. This study determines the diversity (number of alleles and heterozygosity), pedigree assignment and effective population size over two generations of tetraploid production. A significant drop in diversity was observed over two successive generations of tetraploid oysters spawned in 2008 and in 2011, likely due to different numbers of broodstock used. Similar to diploids, pedigree assignment in tetraploids showed unequal parental contributions and an effective population size smaller than the census population, thus the potential for inbreeding to occur in the future is high. © 2014.


Miller P.A.,University of Tasmania | Miller P.A.,Seafood Cooperative Research Center | Elliott N.G.,CSIRO | Vaillancourt R.E.,University of Tasmania | And 2 more authors.
Aquaculture Research | Year: 2016

Triploid production in aquaculture is increasing because of their more profitable growth and reproduction traits. Triploids are mostly produced through mass spawning techniques, meaning that exact pedigree is unknown. The ability to trace the pedigree of high performing triploids would allow selection of broodstock to perpetuate triploids of greater economic value. This study aimed to develop a method of determining parental assignment in triploids and test its accuracy on triploid oysters. Using a likelihood approach and accounting for null allele frequencies, a method was developed which proved to be efficient at determining the pedigree of triploid oysters. This method was able to provide accurate pedigree on simulated data and two commercial cohorts of triploid oysters. The analysis of the triploid cohorts showed that mass spawning to produce triploid oysters, like that for diploid and tetraploids, results in a strong bias in parental contributions, with the effective population size being 34-49% lower than the census population. This highlights the need for pedigree control in breeding programs and indicates that the ability to determine parentage of triploids will be a valuable tool for breeding programs. © 2016 John Wiley & Sons Ltd.

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