Interspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish sp...Interspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish species in China. We conducted 2 × 2 reciprocal crosses to determine whether these two species can cross-fertilize and their hybrids can hatch, survive and perform heterosis. Fertilization was found symmetrical without delay. The rate of fertilization success of C. angulata ♀× C. ariakensis ♂ was lower than that of C. ariakensis ♀× C. angulata ♂, and the success rate of both hybridizations was lower than that of two intraspecific crosses each. During the planktonic period, survival rate of the progeny was lower in the hybrid crosses than in the intraspecific crosses. On day 360, mean shell height of the progeny of C. angulata ♀× C. angulata ♂ was highest, which was followed by that of C. angulata ♀× C. ariakensis ♂, C. ariakensis ♀× C. ariakensis ♂ and C. ariakensis ♀× C. angulata ♂ in a descending order. Morphology of adults produced by the hybrid crosses was similar to that of C. angulata. Both hybrids underwent normal gonad development and produced mature gametes in the mating season. This study provided new insights into the quantitative traits in interspecific crosses of Crassostrea species, thus being of guidance value for selective breeding of oyster.展开更多
Accurate quantification of transcripts using quantitative real-time polymerase chain reaction(q PCR) depends on the identification of reliable reference genes for normalization. This study aimed to identify and valida...Accurate quantification of transcripts using quantitative real-time polymerase chain reaction(q PCR) depends on the identification of reliable reference genes for normalization. This study aimed to identify and validate seven reference genes, including actin-2(A CT- 2), elongation factor 1 alpha(E F- 1α), elongation factor 1 beta(E F- 1β), glyceraldehyde-3-phosphate dehydrogenase(G APDH), ubiquitin( UBQ), β-tubulin(β- TUB), and 18 S ribosomal RNA, from Crassostrea angulata, a valuable marine bivalve cultured worldwide. Transcript levels of the candidate reference genes were examined using q PCR analysis and showed differential expression patterns in the mantle, gill, adductor muscle, labial palp, visceral mass, hemolymph and gonad tissues. Quantitative data were analyzed using the ge Norm software to assess the expression stability of the candidate reference genes, revealing that β- TUB and UBQ were the most stable genes. The commonly used G APDH and 18 SrRNA showed low stability, making them unsuitable candidates in this system. The expression pattern of the G protein β-subunit gene( Gβ) across tissue types was also examined and normalized to the expression of each or both of U BQ and β- TUB as internal controls. This revealed consistent trends with all three normalization approaches, thus validating the reliability of UBQ and β- TUB as optimal internal controls. The study provides the first validated reference genes for accurate data normalization in transcript profiling in C rassostrea angulata, which will be indispensable for further functional genomics studies in this economically valuable marine bivalve.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
基金supported by the National Natural Science Foundation of China(Grant No.31172403)the National Key Basic Research Development Planning Project(Grant No.2010CB126406)
文摘Interspecific hybridization can generate heterosis, which is proven to be a useful tool in selective breeding programs for oyster culture. Crassostrea angulata and C. ariakensis are two important economic shellfish species in China. We conducted 2 × 2 reciprocal crosses to determine whether these two species can cross-fertilize and their hybrids can hatch, survive and perform heterosis. Fertilization was found symmetrical without delay. The rate of fertilization success of C. angulata ♀× C. ariakensis ♂ was lower than that of C. ariakensis ♀× C. angulata ♂, and the success rate of both hybridizations was lower than that of two intraspecific crosses each. During the planktonic period, survival rate of the progeny was lower in the hybrid crosses than in the intraspecific crosses. On day 360, mean shell height of the progeny of C. angulata ♀× C. angulata ♂ was highest, which was followed by that of C. angulata ♀× C. ariakensis ♂, C. ariakensis ♀× C. ariakensis ♂ and C. ariakensis ♀× C. angulata ♂ in a descending order. Morphology of adults produced by the hybrid crosses was similar to that of C. angulata. Both hybrids underwent normal gonad development and produced mature gametes in the mating season. This study provided new insights into the quantitative traits in interspecific crosses of Crassostrea species, thus being of guidance value for selective breeding of oyster.
基金Supported by the National Natural Science Foundation of China(No.41176113)the National Basic Research Program of China(973 Program)(No.2010CB126403)+1 种基金the Changjiang Scholars Program for Innovative Research Team in Universities(No.IRT0941)the Earmarked Fund for Modern Agro-Industry Technology Research System(No.nycytx-47)
文摘Accurate quantification of transcripts using quantitative real-time polymerase chain reaction(q PCR) depends on the identification of reliable reference genes for normalization. This study aimed to identify and validate seven reference genes, including actin-2(A CT- 2), elongation factor 1 alpha(E F- 1α), elongation factor 1 beta(E F- 1β), glyceraldehyde-3-phosphate dehydrogenase(G APDH), ubiquitin( UBQ), β-tubulin(β- TUB), and 18 S ribosomal RNA, from Crassostrea angulata, a valuable marine bivalve cultured worldwide. Transcript levels of the candidate reference genes were examined using q PCR analysis and showed differential expression patterns in the mantle, gill, adductor muscle, labial palp, visceral mass, hemolymph and gonad tissues. Quantitative data were analyzed using the ge Norm software to assess the expression stability of the candidate reference genes, revealing that β- TUB and UBQ were the most stable genes. The commonly used G APDH and 18 SrRNA showed low stability, making them unsuitable candidates in this system. The expression pattern of the G protein β-subunit gene( Gβ) across tissue types was also examined and normalized to the expression of each or both of U BQ and β- TUB as internal controls. This revealed consistent trends with all three normalization approaches, thus validating the reliability of UBQ and β- TUB as optimal internal controls. The study provides the first validated reference genes for accurate data normalization in transcript profiling in C rassostrea angulata, which will be indispensable for further functional genomics studies in this economically valuable marine bivalve.
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.
