Iwagaki oyster,Crassostrea nippona,widely distributes along the seashore of Eastern Asia,and has been considered to be a potential breeding species due to its delicious taste and high commercial value.In order to stud...Iwagaki oyster,Crassostrea nippona,widely distributes along the seashore of Eastern Asia,and has been considered to be a potential breeding species due to its delicious taste and high commercial value.In order to study its genetic background and population structure,we developed 46 novel polymorphic microsatellite markers using next-generation sequencing technique and characterized them in 30 individuals.The number of alleles ranged from 3 to 22,while the observed and expected heterozygosities varied from 0.133 to 1.000 and 0.455 to 0.949,respectively.Fifteen microsatellite markers were selected and grouped into five highly informative multiplex PCRs for C.nippona.We evaluated and validated these multiplex PCRs in a cultured population including 173 candidate parents and 486 offspring.In actual parentage analysis,80%of the offspring were correctly assigned to their parental pairs using three multiplex PCRs.Furthermore,the success rate of parentage assignment reached 96%when the other two multiplex PCRs were added.These 46 microsatellite loci with high variability and the five multiplex PCRs described here provide a powerful tool for pedigree reconstruction,resource conservation and selective breeding program of C.nippona.展开更多
Pinctada martensii is an important shellfish for the production of sea pearls in China.To improve the growth performance of P.martensii,we successfully established three complete diallel crosses using three new variet...Pinctada martensii is an important shellfish for the production of sea pearls in China.To improve the growth performance of P.martensii,we successfully established three complete diallel crosses using three new varieties of P.martensii,which were named Haiyou No.1,Haixuan No.1,and Nanke No.1,to investigate the growth performance of each self-cross line and hybrid line in Beihai,Guangxi Zhuang Autonomous Region,China.Generally,high fertilization and hatching rates were observed in the experiment,suggesting that there was no sperm-egg recognition barrier among these three P.martensii varieties.The survival rate of the self-cross lines was relatively higher than that of hybrid lines,and♀‘Haixuan No.1’×♂‘Haiyou No.1’maintained a high survival rate during the grow-out stage.The shell length and width were affected by the genotypes as well as the interaction between the genotypes and environmental factors on day 400.The variances of the general combining abilities(GCA)and specific combining abilities(SCA)for shell length and width were the result of both additive genetic variance and nonadditive genetic variance.When Haixuan No.1 was the female parent and Nanke No.1 was the male parent,the GCA for shell length and width were both positive on day 400.The heterosis of Haixuan No.1 and Nanke No.1 in terms of shell length and width was positive.From the resulting combining ability and heterosis,♀‘Haixuan No.1’×♂‘Nanke No.1’was considered an ideal hatchery method to improve the growth performance of P.martensii.Our results therefore demonstrated that crossbreeding among these three new varieties can further improve the growth performance of P.martensii.展开更多
To detect the intergeneric hybridization between the oyster Crassostrea angulata and Saccostrea cucullata coexisting along the southern coast of China, reciprocal crosses were conducted between the two species. Barrie...To detect the intergeneric hybridization between the oyster Crassostrea angulata and Saccostrea cucullata coexisting along the southern coast of China, reciprocal crosses were conducted between the two species. Barriers for sperm recognizing, binding, penetrating the egg, and forming the pronucleus were detected by fluorescence staining. From the results, although fertilization success was observed in hybrid crosses, the overall fertilization rate was lower than that of intraspecific crosses. A large number of hybrid larvae died at 6–8 d after hatching, and those survived could not complete metamorphosis. C. angulata ♀× S. cucullata ♂ larvae had a growth rate similar to that of the maternal species, whereas S. cucullata ♀× C. angulata ♂ larvae grew the slowest among all crosses. Molecular genetics analysis revealed that hybrid progeny were amphimixis hybrids. This study demonstrated that hybrid embryos generated by crossing C. angulata and S. cucullata could develop normally to the larval state, but could not complete metamorphosis and then develop to the spat stage. Thus, there is a post-reproductive isolation between C. angulata and S. cucullata.展开更多
Crossbreeding is an effective approach to manage the genetic decline in aquaculture.One-way hybrids of Crassostrea sikamea(♀)and Crassostrea gigas(♂)have advantages in growth traits and adaptation to high temperatur...Crossbreeding is an effective approach to manage the genetic decline in aquaculture.One-way hybrids of Crassostrea sikamea(♀)and Crassostrea gigas(♂)have advantages in growth traits and adaptation to high temperature.Here,we used high-throughput sequencing to analyze the molecular processes in the hybrids under and after thermal stress.The hybrids were cultured in the seawater with an increasing temperature from 25℃to 40℃during 10 hours,which is regarded as the thermal stress stage.Then the temperature decreased from 40℃to 25℃within 2 h,which is regarded as the recovery stage.In this study,1293 significant diffe-rentially expressed genes(DEGs)were obtained under thermal stress,of which 576 were upregulated and 717 were downregulated,and 740 significant differentially expressed genes(DEGs)were obtained in the recovery stage,of which the number of upregulated and downregulated genes was 409 and 331,respectively.The antigen processing and presentation,NOD-like,and NF-kappa B path-ways were significantly enriched during the thermal stress stage.The MAPK and PPAR signaling pathways were significantly enrich-ed during the recovery stage.The HSP70,HSP90,and CANX genes were strongly and rapidly upregulated in the control/thermal stress groups but were slightly less upregulated in the thermal stress/recovery group.These results indicate that the innate immune system or nonspecific immunity was deployed to protect interior tissues from thermal stress.In addition,85%of the mutual DEGs were involved in bidirectional regulation(up/down or down/up)when the oysters were removed from the thermal stress to recover.This study provides preliminary insight into the molecular response of C.sikamea(♀)and C.gigas(♂)hybrids to thermal stress and provides a basis for future studies on temperature-adaptation and the possible expansion of hybrid breeding.展开更多
基金supported by the National Natural Science Foundation of China (No. 31772843)the Natural Sci- ence Foundation of Guangxi Province (No. AA17204080-4)the Fundamental Research Funds for the Central Uni- versities (No. 201762014)
文摘Iwagaki oyster,Crassostrea nippona,widely distributes along the seashore of Eastern Asia,and has been considered to be a potential breeding species due to its delicious taste and high commercial value.In order to study its genetic background and population structure,we developed 46 novel polymorphic microsatellite markers using next-generation sequencing technique and characterized them in 30 individuals.The number of alleles ranged from 3 to 22,while the observed and expected heterozygosities varied from 0.133 to 1.000 and 0.455 to 0.949,respectively.Fifteen microsatellite markers were selected and grouped into five highly informative multiplex PCRs for C.nippona.We evaluated and validated these multiplex PCRs in a cultured population including 173 candidate parents and 486 offspring.In actual parentage analysis,80%of the offspring were correctly assigned to their parental pairs using three multiplex PCRs.Furthermore,the success rate of parentage assignment reached 96%when the other two multiplex PCRs were added.These 46 microsatellite loci with high variability and the five multiplex PCRs described here provide a powerful tool for pedigree reconstruction,resource conservation and selective breeding program of C.nippona.
基金funded by the National Natural Science Foundation of China(No.911221680).
文摘Pinctada martensii is an important shellfish for the production of sea pearls in China.To improve the growth performance of P.martensii,we successfully established three complete diallel crosses using three new varieties of P.martensii,which were named Haiyou No.1,Haixuan No.1,and Nanke No.1,to investigate the growth performance of each self-cross line and hybrid line in Beihai,Guangxi Zhuang Autonomous Region,China.Generally,high fertilization and hatching rates were observed in the experiment,suggesting that there was no sperm-egg recognition barrier among these three P.martensii varieties.The survival rate of the self-cross lines was relatively higher than that of hybrid lines,and♀‘Haixuan No.1’×♂‘Haiyou No.1’maintained a high survival rate during the grow-out stage.The shell length and width were affected by the genotypes as well as the interaction between the genotypes and environmental factors on day 400.The variances of the general combining abilities(GCA)and specific combining abilities(SCA)for shell length and width were the result of both additive genetic variance and nonadditive genetic variance.When Haixuan No.1 was the female parent and Nanke No.1 was the male parent,the GCA for shell length and width were both positive on day 400.The heterosis of Haixuan No.1 and Nanke No.1 in terms of shell length and width was positive.From the resulting combining ability and heterosis,♀‘Haixuan No.1’×♂‘Nanke No.1’was considered an ideal hatchery method to improve the growth performance of P.martensii.Our results therefore demonstrated that crossbreeding among these three new varieties can further improve the growth performance of P.martensii.
文摘To detect the intergeneric hybridization between the oyster Crassostrea angulata and Saccostrea cucullata coexisting along the southern coast of China, reciprocal crosses were conducted between the two species. Barriers for sperm recognizing, binding, penetrating the egg, and forming the pronucleus were detected by fluorescence staining. From the results, although fertilization success was observed in hybrid crosses, the overall fertilization rate was lower than that of intraspecific crosses. A large number of hybrid larvae died at 6–8 d after hatching, and those survived could not complete metamorphosis. C. angulata ♀× S. cucullata ♂ larvae had a growth rate similar to that of the maternal species, whereas S. cucullata ♀× C. angulata ♂ larvae grew the slowest among all crosses. Molecular genetics analysis revealed that hybrid progeny were amphimixis hybrids. This study demonstrated that hybrid embryos generated by crossing C. angulata and S. cucullata could develop normally to the larval state, but could not complete metamorphosis and then develop to the spat stage. Thus, there is a post-reproductive isolation between C. angulata and S. cucullata.
基金supported by the National Natural Sci-ence Foundation of China(No.31172403).
文摘Crossbreeding is an effective approach to manage the genetic decline in aquaculture.One-way hybrids of Crassostrea sikamea(♀)and Crassostrea gigas(♂)have advantages in growth traits and adaptation to high temperature.Here,we used high-throughput sequencing to analyze the molecular processes in the hybrids under and after thermal stress.The hybrids were cultured in the seawater with an increasing temperature from 25℃to 40℃during 10 hours,which is regarded as the thermal stress stage.Then the temperature decreased from 40℃to 25℃within 2 h,which is regarded as the recovery stage.In this study,1293 significant diffe-rentially expressed genes(DEGs)were obtained under thermal stress,of which 576 were upregulated and 717 were downregulated,and 740 significant differentially expressed genes(DEGs)were obtained in the recovery stage,of which the number of upregulated and downregulated genes was 409 and 331,respectively.The antigen processing and presentation,NOD-like,and NF-kappa B path-ways were significantly enriched during the thermal stress stage.The MAPK and PPAR signaling pathways were significantly enrich-ed during the recovery stage.The HSP70,HSP90,and CANX genes were strongly and rapidly upregulated in the control/thermal stress groups but were slightly less upregulated in the thermal stress/recovery group.These results indicate that the innate immune system or nonspecific immunity was deployed to protect interior tissues from thermal stress.In addition,85%of the mutual DEGs were involved in bidirectional regulation(up/down or down/up)when the oysters were removed from the thermal stress to recover.This study provides preliminary insight into the molecular response of C.sikamea(♀)and C.gigas(♂)hybrids to thermal stress and provides a basis for future studies on temperature-adaptation and the possible expansion of hybrid breeding.
