Chromosome behavior in meiosis was studied by ail-drying, C-banding and surface-spreading methods in female intersexes of artificial triploid transparent-colored crucian carp (Corassius auratus). Chromosome pairing an...Chromosome behavior in meiosis was studied by ail-drying, C-banding and surface-spreading methods in female intersexes of artificial triploid transparent-colored crucian carp (Corassius auratus). Chromosome pairing and contraction were obviously asynchronous. The preferential pairing of two homologous chromosomes was the major pattern of chromosome pairing, and a few triple pairing, repeated pairing, telomere or centromere associating and multiple pairing were also observed in the pachytene cells. The metaphase I cells were main-ly composed of univalents, bivalents and trivalents, as well as a few of other multivalents, such as tetravalents, pentavalents, hexavalents and heptavalents, were also found in some metaphase I cells. The chromosome elements including uni-, bi-, tri- and other multivalents varied considerably among the metaphase I cells, and the associating patterns of multivalents were also diverse. Some 6 n and 12 n cells, in which premeiotic endomitosis occurred once or twice, were found at the prophase and first metaphase of meiosis, and the pairing and associating patterns were basically similar to that of the triploid cells.展开更多
Sex-determination pathways are extremely diverse.Understanding the mechanism of sex determination in insects is important for genetic manipulation of the pest population and for breeding of economically valuable insec...Sex-determination pathways are extremely diverse.Understanding the mechanism of sex determination in insects is important for genetic manipulation of the pest population and for breeding of economically valuable insects.Although sex determi-nation has been well characterized in the model species Drosophila melanogaster,little is known about this pathway in Stratiomyidae.In the present study,we first identified the Drosophila intersex(ix)homolog in Hermetia illucens,also known as the black soldier fly,which belongs to the Stratiomyidae family and which is an important insect for the con-version of various organic wastes.Phylogenetic analyses and multiple sequence alignment revealed that Hix is conserved compared with Drosophila.We showed that Hix is highly expressed in internal genitalia.Disruption of the Hix gene using CRISPR/Cas9 resulted in female-specific defects in external genitalia and abnormal and undersized ovaries.Taken together,our study furthers our understanding of sex determination in insects and could facilitatebreedingof H.illucens.展开更多
Although 1,1-dichloro-2,2-bis（p-chlorophenyl）-ethylene （p,p′-DDE）, the major and most persistent metabolite of dichlorodiphenyltrichloroethane （DDT）, was continually detected in wild fishes that showed abnormal...Although 1,1-dichloro-2,2-bis（p-chlorophenyl）-ethylene （p,p′-DDE）, the major and most persistent metabolite of dichlorodiphenyltrichloroethane （DDT）, was continually detected in wild fishes that showed abnormal gonad development such as intersex, little is known about the impact of p,p′-DDE exposure on gonad development in fishes. To survey the effects of p,p′-DDE on gonadal development and gene expressions, male juvenile （20-d post hatch） Japanese medaka （Oryzias latipes） was exposed to 1, 5, 20, and 100 μg/L p,p′-DDE for two months. Increased hepatosomatic index （HSI） and decreased gonadosomatic index （GSI） were found in the p,p′-DDE-treated groups. Intersex was found in 100 μg/L p,p′-DDE exposure group, as well as 100 ng/L 17α-ethynylestradiol （EE2） group. By quantitative real-time RT-PCR, it was found that gene expressions of vitellogenins （VTG-1, VTG-2）, choriogenins （CHG-H, CHG-L）, and estrogen receptor α （ER-α） in the liver of the fish were significantly up-regulated by p,p′-DDE exposure. VTG-1 and VTG- 2 were recommended as the preferred biomarker for assessing anti-androgenic p,p′-DDE because they were the highest up-regulated among the genes and showed good dose-response relationship. The up-regulated ER-α suggested that a potential synergetic effect would occur when p,p′-DDE coexists with other ER-α-binding endocrine-disrupting chemicals （EDCs）.展开更多
【目的】分析奶山羊间性个体的遗传背景,探讨间性个体发生的遗传机制,为山羊性别调控以及性别决定的研究提供参考。【方法】通过核型分析、特异性性别调控基因(Sex-determining region of Y chromosome,SRY)的PCR扩增以及AFLP(Amplified...【目的】分析奶山羊间性个体的遗传背景,探讨间性个体发生的遗传机制,为山羊性别调控以及性别决定的研究提供参考。【方法】通过核型分析、特异性性别调控基因(Sex-determining region of Y chromosome,SRY)的PCR扩增以及AFLP(Amplified fragment length polymorphism)指纹图谱分析等方法,研究西农萨能羊间性个体的遗传本质。【结果】间性山羊与正常母山羊的核型一致,为58+XX;间性个体基因组中未能扩增出SRY基因;AFLP指纹图谱分析发现,有9对引物扩增出清晰的条带,共1 833条,片段长度为70～500bp,9对引物的扩增结果差异明显,表现出丰富的多态性,共获得611个多态位点,占总扩增条带数的33.3%,但在基因组水平上间性山羊与正常母山羊个体并没有大的差异。【结论】根据试验结果推测,间性山羊的出现并非是由个体基因组发生突变造成的,可能是在性别决定过程中某个因子的调控出现差错,从而导致胚胎在发育过程中偏离雌性轨道而产生间性山羊个体,其具体机制有待进一步研究。展开更多
基金This work was supported in part by the Youth Grant(862001)President Grant from the Chinese Academy of Sciences.
文摘Chromosome behavior in meiosis was studied by ail-drying, C-banding and surface-spreading methods in female intersexes of artificial triploid transparent-colored crucian carp (Corassius auratus). Chromosome pairing and contraction were obviously asynchronous. The preferential pairing of two homologous chromosomes was the major pattern of chromosome pairing, and a few triple pairing, repeated pairing, telomere or centromere associating and multiple pairing were also observed in the pachytene cells. The metaphase I cells were main-ly composed of univalents, bivalents and trivalents, as well as a few of other multivalents, such as tetravalents, pentavalents, hexavalents and heptavalents, were also found in some metaphase I cells. The chromosome elements including uni-, bi-, tri- and other multivalents varied considerably among the metaphase I cells, and the associating patterns of multivalents were also diverse. Some 6 n and 12 n cells, in which premeiotic endomitosis occurred once or twice, were found at the prophase and first metaphase of meiosis, and the pairing and associating patterns were basically similar to that of the triploid cells.
基金funded by the National Key Research and Development Project of China(2021YFD1301000).
文摘Sex-determination pathways are extremely diverse.Understanding the mechanism of sex determination in insects is important for genetic manipulation of the pest population and for breeding of economically valuable insects.Although sex determi-nation has been well characterized in the model species Drosophila melanogaster,little is known about this pathway in Stratiomyidae.In the present study,we first identified the Drosophila intersex(ix)homolog in Hermetia illucens,also known as the black soldier fly,which belongs to the Stratiomyidae family and which is an important insect for the con-version of various organic wastes.Phylogenetic analyses and multiple sequence alignment revealed that Hix is conserved compared with Drosophila.We showed that Hix is highly expressed in internal genitalia.Disruption of the Hix gene using CRISPR/Cas9 resulted in female-specific defects in external genitalia and abnormal and undersized ovaries.Taken together,our study furthers our understanding of sex determination in insects and could facilitatebreedingof H.illucens.
基金supported by the National Natural Science Foundation of China(No.40632009,20607002)the National Basic Research Program(973)of China(No.2007CB407304).
文摘Although 1,1-dichloro-2,2-bis（p-chlorophenyl）-ethylene （p,p′-DDE）, the major and most persistent metabolite of dichlorodiphenyltrichloroethane （DDT）, was continually detected in wild fishes that showed abnormal gonad development such as intersex, little is known about the impact of p,p′-DDE exposure on gonad development in fishes. To survey the effects of p,p′-DDE on gonadal development and gene expressions, male juvenile （20-d post hatch） Japanese medaka （Oryzias latipes） was exposed to 1, 5, 20, and 100 μg/L p,p′-DDE for two months. Increased hepatosomatic index （HSI） and decreased gonadosomatic index （GSI） were found in the p,p′-DDE-treated groups. Intersex was found in 100 μg/L p,p′-DDE exposure group, as well as 100 ng/L 17α-ethynylestradiol （EE2） group. By quantitative real-time RT-PCR, it was found that gene expressions of vitellogenins （VTG-1, VTG-2）, choriogenins （CHG-H, CHG-L）, and estrogen receptor α （ER-α） in the liver of the fish were significantly up-regulated by p,p′-DDE exposure. VTG-1 and VTG- 2 were recommended as the preferred biomarker for assessing anti-androgenic p,p′-DDE because they were the highest up-regulated among the genes and showed good dose-response relationship. The up-regulated ER-α suggested that a potential synergetic effect would occur when p,p′-DDE coexists with other ER-α-binding endocrine-disrupting chemicals （EDCs）.
文摘【目的】分析奶山羊间性个体的遗传背景,探讨间性个体发生的遗传机制,为山羊性别调控以及性别决定的研究提供参考。【方法】通过核型分析、特异性性别调控基因(Sex-determining region of Y chromosome,SRY)的PCR扩增以及AFLP(Amplified fragment length polymorphism)指纹图谱分析等方法,研究西农萨能羊间性个体的遗传本质。【结果】间性山羊与正常母山羊的核型一致,为58+XX;间性个体基因组中未能扩增出SRY基因;AFLP指纹图谱分析发现,有9对引物扩增出清晰的条带,共1 833条,片段长度为70～500bp,9对引物的扩增结果差异明显,表现出丰富的多态性,共获得611个多态位点,占总扩增条带数的33.3%,但在基因组水平上间性山羊与正常母山羊个体并没有大的差异。【结论】根据试验结果推测,间性山羊的出现并非是由个体基因组发生突变造成的,可能是在性别决定过程中某个因子的调控出现差错,从而导致胚胎在发育过程中偏离雌性轨道而产生间性山羊个体,其具体机制有待进一步研究。
