title: Genetic Variation and Breeding Signature in Mass Selection Lines of the Pacific Oyster (Crassostrea gigas) Assessed by SNP Markers.
abstract: In breeding industries, a challenging problem is how to keep genetic diversity over generations. To investigate genetic variation and identify breeding signatures in mass selected lines of Pacific oyster (Crassostrea gigas), three sixth-generation selected lines and four wild populations were assessed using 103 single nucleotide polymorphism (SNP) markers. The genetic diversity data indicated that the selected lines exhibited a significant reduction in the observed heterozygosity and observed number of alleles per locus compared with the wild populations (P≤0.05), indicating the selected lines tended to lose genetic diversity contrasted with the wild populations. The unweighted pair-group method with arithmetic mean (UPGMA) analysis showed that the wild populations and selected lines were not separated into two groups. Using four outlier tests, a total of 17 loci were found under selection at two levels. The global outlier detection suggested that 4 common outlier loci were subject to selection using both the hierarchical island model and Bayesian likelihood approaches. At regional level, 3 SNPs were detected as outlier using at least two outlier tests and one outlier SNP (CgSNP309) was overlapped in the two wild-selected population comparisons. The candidate outlier SNPs provide valuable resources for future association studies in C. gigas.
authors.affiliation: Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Zhong
authors.affiliation: Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Feng
authors.affiliation: Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yu
authors.affiliation: Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, China.
authors.forename: Lingfeng
authors.initials: L
authors.lastname: Kong
authors.affiliation: Key Laboratory of Mariculture Ministry of Education, Ocean University of China, Qingdao, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
mesh_terms: D000818:Animals; D001947:Breeding; D049896:Crassostrea / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation; D005828:Genetics, Population; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic