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Liu Y.,Chinese Academy of Fishery Sciences | Wang G.,Beidaihe Central Experiment Station | Liu Y.,Northeast Agricultural University | Hou J.,Northeast Agricultural University | And 5 more authors.
Aquaculture | Year: 2012

Mitotic gynogenetic diploid or doubled haploid Japanese flounder Paralichthys olivaceus were produced by activating eggs with UV irradiated sperm of red sea bream (Pagrus major), followed by hydrostatic pressure treatment to block the first mitotic division. To verify the doubled haploid, we measured the homozygosity of 21 maternally heterozygous microsatellite loci that are located in the telomeric region of chromosomes. These 21 loci have large marker-centromere distances of 43 to 50. cM estimated from four meiotic gynogenetic diploid lines, suggesting the location at telomeric regions of chromosomes. These 21 loci cover 16 out of the total 24 linkage groups of Japanese flounder. Microsatellite genotyping of these 21 markers in four mitotic gynogentic diploid lines shows that 75% (58 out of 77) individuals are homozygous at all 21 loci, indicating doubled haploids. The other 25% are heterozygous at 1 to 13 loci, probably representing spontaneously occurring meiotic gynogenetic diploids. These results demonstrate the high efficiency of generating doubled haploids in just one generation by mitotic gynogenesis. We have used these doubled haploids to successfully generate clonal lines via a second round of gynogenesis. © 2011 Elsevier B.V. Source


Liu Y.X.,Chinese Academy of Fishery Sciences | Han H.Z.,Shanghai Ocean University | Wang Q.L.,Shanghai Ocean University | Jiang L.,Chinese Academy of Fishery Sciences | And 6 more authors.
Journal of Fish Biology | Year: 2013

A set of 72 microsatellite markers distributed evenly among 24 linkage groups were selected from the published genetic linkage maps of Japanese flounder Paralichthys olivaceus. In two normal diploid full-sib families, the test for Mendelian inheritance showed that genotypic segregation deviations were not significant at all analysed loci. To estimate microsatellite-centromere map distances, four meiotic gynogenetic diploid lines were produced by the activation of eggs using UV irradiated sperm of red seabream Pagrus major and cold-shock treatment to block the extrusion of the second polar body. Under the assumption of complete interference, 21 markers were located in the centromeric region, 39 in the telomeric region and the rest in the intermediate region of linkage groups. A total of 192 mitotic gynogenetic diploids from one spawn were identified by these markers. Genotype analysis showed that the number of homozygous individuals decreased as microsatellite-centromere map distance increased on each linkage group. © 2013 The Author. Journal of Fish Biology © 2013 The Fisheries Society of the British Isles. Source


Liu Y.X.,Chinese Academy of Fishery Sciences | Sun Z.H.,Beidaihe Central Experiment Station | Wang Y.F.,Beidaihe Central Experiment Station | Yang R.Q.,Chinese Academy of Fishery Sciences
Journal of Fish Biology | Year: 2015

The objective of this study was to estimate genetic parameters of main length ratios associated with morphological traits in Paralichthys olivaceus. At 180, 240 and 360 days of age, body length (L1), head length (L2), body depth (L3), caudal peduncle depth (L4) and caudal-peduncle length (L5) were observed in 4757-5224 individuals from 52 full-sib families. Based on these observed traits, the main length-ratio traits including L3:L1, L2:L1, L5:L1 and L4:L3 were constructed. Three single-trait animal models were used to examine the phenotypic variation of length-ratio traits and were compared using the likelihood ratio test. As a result, the optimal model for all the analysed traits was determined as the model with the fixed, additive genetic and full-sib family effects. Using the optimal model, animal model analysis for single trait showed that heritabilities were estimated to be low, ranging from 0·122 to 0·276. The estimates for all length-ratio traits decreased while the days of age increased except for L3:L1. Multivariate animal model analysis indicated that within and among days of age, genetic correlations between length-ratio traits were different in the direction and magnitude. Genetic parameter estimation of main length ratios would be helpful for genetic improvement of body shape in P. olivaceus. © 2015 The Fisheries Society of the British Isles. Source

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