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Mitsuru Sakaizumi - One of the best experts on this subject based on the ideXlab platform.
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Inter- and Intraspecific Variation in Sex Hormone-Induced Sex-Reversal in Medaka, Oryzias Latipes and Oryzias sakaizumii
Zoological Science, 2019Co-Authors: Taijun Myosho, Tadashi Sato, Satoshi Hamaguchi, Hiroka Nishiyama, Akiho Watanabe, Jun Yamamoto, Tetsuro Okamura, Yuta Onishi, Rei Fujimaki, Mitsuru SakaizumiAbstract:We compared sex-reversal ratios induced by 17α-methyltestosterone (MT) and 17β-estradiol (E2) exposure in two inbred medaka strains: Hd-rR derived from Oryzias Latipes and HNI-II from O. sakaizumii. All MT exposures (0.2–25 ng mL–1) induced complete XX sex-reversal in HNI-II. Although MT exposure at 0.2 ng mL–1 induced XX sex-reversal at > 95% in Hd-rR, other concentrations tested caused XX sex-reversal at lower frequencies ( 10 ng mL–1, and in all fish feminization occurred 500 ng mL–1. In HNI-II, E2 induced XY sex-reversal at 50 and 250 ng mL–1, but only at rates below 20%. To clarify whether the strain differences in sex hormone-induced sex-reversal are characteristic of each species, we examined the effects of MT and E2 exposure on sex differentiation in five and two additional strains or wild stocks/populations of O. Latipes and O. sakaizumii, respectively. MT exposure induced low XX and high XY sex-reversal rates in O. Latipes, except in the Shizuoka population, but the trend was reversed in O. sakaizumii. Furthermore, E2-induced XY sex-reversal rates varied intraspecifically in O. Latipes. Our results demonstrated that sensitivity to MT and E2 varied within O. Latipes species. To evaluate the ecological impacts of environmental chemicals using medaka, it is important to define not only the species, but the strains, stocks, and populations to obtain accurate results.
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The origin of the large metacentric chromosome pair in Chinese medaka ( Oryzias sinensis )
Ichthyological Research, 2012Co-Authors: Taijun Myosho, Yusuke Takehana, Tadashi Sato, Satoshi Hamaguchi, Mitsuru SakaizumiAbstract:Japanese medakas (Oryzias Latipes and Oryzias sakaizumii) have 48 chromosomes, while the Chinese medaka (Oryzias sinensis) has 46 chromosomes, including one pair of large metacentric chromosomes. Linkage analysis using O. sakaizumii and O. sinensis strains showed that DNA markers in linkage groups (LG) 11 and 13 were tightly linked. Centromeric genomic clones of LG 11 and 13 derived from an O. Latipes strain hybridized across the centromeres of the pair of large metacentric chromosomes in an O. sinensis strain. These results demonstrate that the large metacentric chromosome pair was derived from two pairs of acrocentric chromosomes (LG 11 and 13) through Robertsonian fusion.
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An autosomal locus controls sex reversal in interspecific XY hybrids of the medaka fishes
Heredity, 2011Co-Authors: Mariko Kato, Yusuke Takehana, Mitsuru Sakaizumi, Kiyoshi Naruse, Y Fukuda, Satoshi HamaguchiAbstract:Although the two medaka species Oryzias Latipes and O. curvinotus share the sex-determining gene Dmy, XY sex reversal occurs in interspecific hybridization between O. Latipes females of the Hd-rR inbred strain and O. curvinotus males. In this Hd-rR-curvinotus mating, all XX and XY hybrids developed as females. In this study, we used another O. Latipes inbred strain (HNI) for the mating, and found that 23% of XY hybrids developed as males, although all XX and the remaining XY hybrids developed as females. Linkage analysis using 236 XY hybrid males obtained from (Hd-rR × HNI) F1 females showed that a single major locus, Hybrid maleless (Hml), on autosomal linkage group 17, contributed to the strain difference in the XY sex reversal. Furthermore, we found that crossing females of a different O. Latipes inbred strain, HO4C, did not cause XY sex reversal in the interspecific hybrids, and that the XY hybrids from (Hd-rR × HO4C) F1 females showed a 1:1 sex ratio. XY hybrid males had the HO4C allele at sequence-tagged site loci around the Hml locus whereas XY females had the Hd-rR allele, confirming the strong contribution of this locus to XY sex reversal. Reverse transcriptase PCR analysis showed a reduced expression of Dmycurvinotus in XY fry of the Hd-rR-curvinotus hybrids at hatching. These results suggest that the Hd-rR allele at the Hml locus interfere with the function of Dmycurvinotus on a hybrid background, thus resulting in XY sex reversal.
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A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
Heredity, 2010Co-Authors: Mariko Kato, Mitsuru Sakaizumi, Y Takehana, S. HamaguchiAbstract:Oryzias Latipes and Oryzias curvinotus are closely related medaka species that have the common sex-determining gene, DMY, on their homologous Y chromosomes. We previously reported that sex-reversed XY females were produced in hybrids between O. curvinotus females and O. Latipes males (Hd-rR inbred strain). In this study we used HNI inbred strain males of O. Latipes for mating with O. curvinotus females, and found that all the XY hybrids developed as males. To map the factor responsible for this strain-specific XY sex reversal, O. curvinotus females were mated with two Y-congenic strains (HNI.Y^Hd-rR and Hd-rR.Y^HNI) and a recombinant congenic strain (Hd-rR.Y^HNI rr ). HNI.Y^Hd-rR produced sex-reversed females in the XY hybrids, whereas no sex-reversed females were obtained in the XY hybrids from Hd-rR.Y^HNI and Hd-rR.Y^HNI rr , demonstrating that a small region on the Y chromosome, which includes DMY , is responsible for the XY sex reversal. Sex-reversed hybrids were only produced in the presence of the Y-chromosomal region derived from the Hd-rR strain, suggesting that missense or regulatory mutations specific to the Hd-rR Y-chromosomal region induce the sex reversal.
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A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
Heredity, 2009Co-Authors: Mariko Kato, Yusuke Takehana, Mitsuru Sakaizumi, Satoshi HamaguchiAbstract:A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
Satoshi Hamaguchi - One of the best experts on this subject based on the ideXlab platform.
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Inter- and Intraspecific Variation in Sex Hormone-Induced Sex-Reversal in Medaka, Oryzias Latipes and Oryzias sakaizumii
Zoological Science, 2019Co-Authors: Taijun Myosho, Tadashi Sato, Satoshi Hamaguchi, Hiroka Nishiyama, Akiho Watanabe, Jun Yamamoto, Tetsuro Okamura, Yuta Onishi, Rei Fujimaki, Mitsuru SakaizumiAbstract:We compared sex-reversal ratios induced by 17α-methyltestosterone (MT) and 17β-estradiol (E2) exposure in two inbred medaka strains: Hd-rR derived from Oryzias Latipes and HNI-II from O. sakaizumii. All MT exposures (0.2–25 ng mL–1) induced complete XX sex-reversal in HNI-II. Although MT exposure at 0.2 ng mL–1 induced XX sex-reversal at > 95% in Hd-rR, other concentrations tested caused XX sex-reversal at lower frequencies ( 10 ng mL–1, and in all fish feminization occurred 500 ng mL–1. In HNI-II, E2 induced XY sex-reversal at 50 and 250 ng mL–1, but only at rates below 20%. To clarify whether the strain differences in sex hormone-induced sex-reversal are characteristic of each species, we examined the effects of MT and E2 exposure on sex differentiation in five and two additional strains or wild stocks/populations of O. Latipes and O. sakaizumii, respectively. MT exposure induced low XX and high XY sex-reversal rates in O. Latipes, except in the Shizuoka population, but the trend was reversed in O. sakaizumii. Furthermore, E2-induced XY sex-reversal rates varied intraspecifically in O. Latipes. Our results demonstrated that sensitivity to MT and E2 varied within O. Latipes species. To evaluate the ecological impacts of environmental chemicals using medaka, it is important to define not only the species, but the strains, stocks, and populations to obtain accurate results.
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The origin of the large metacentric chromosome pair in Chinese medaka ( Oryzias sinensis )
Ichthyological Research, 2012Co-Authors: Taijun Myosho, Yusuke Takehana, Tadashi Sato, Satoshi Hamaguchi, Mitsuru SakaizumiAbstract:Japanese medakas (Oryzias Latipes and Oryzias sakaizumii) have 48 chromosomes, while the Chinese medaka (Oryzias sinensis) has 46 chromosomes, including one pair of large metacentric chromosomes. Linkage analysis using O. sakaizumii and O. sinensis strains showed that DNA markers in linkage groups (LG) 11 and 13 were tightly linked. Centromeric genomic clones of LG 11 and 13 derived from an O. Latipes strain hybridized across the centromeres of the pair of large metacentric chromosomes in an O. sinensis strain. These results demonstrate that the large metacentric chromosome pair was derived from two pairs of acrocentric chromosomes (LG 11 and 13) through Robertsonian fusion.
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An autosomal locus controls sex reversal in interspecific XY hybrids of the medaka fishes
Heredity, 2011Co-Authors: Mariko Kato, Yusuke Takehana, Mitsuru Sakaizumi, Kiyoshi Naruse, Y Fukuda, Satoshi HamaguchiAbstract:Although the two medaka species Oryzias Latipes and O. curvinotus share the sex-determining gene Dmy, XY sex reversal occurs in interspecific hybridization between O. Latipes females of the Hd-rR inbred strain and O. curvinotus males. In this Hd-rR-curvinotus mating, all XX and XY hybrids developed as females. In this study, we used another O. Latipes inbred strain (HNI) for the mating, and found that 23% of XY hybrids developed as males, although all XX and the remaining XY hybrids developed as females. Linkage analysis using 236 XY hybrid males obtained from (Hd-rR × HNI) F1 females showed that a single major locus, Hybrid maleless (Hml), on autosomal linkage group 17, contributed to the strain difference in the XY sex reversal. Furthermore, we found that crossing females of a different O. Latipes inbred strain, HO4C, did not cause XY sex reversal in the interspecific hybrids, and that the XY hybrids from (Hd-rR × HO4C) F1 females showed a 1:1 sex ratio. XY hybrid males had the HO4C allele at sequence-tagged site loci around the Hml locus whereas XY females had the Hd-rR allele, confirming the strong contribution of this locus to XY sex reversal. Reverse transcriptase PCR analysis showed a reduced expression of Dmycurvinotus in XY fry of the Hd-rR-curvinotus hybrids at hatching. These results suggest that the Hd-rR allele at the Hml locus interfere with the function of Dmycurvinotus on a hybrid background, thus resulting in XY sex reversal.
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A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
Heredity, 2009Co-Authors: Mariko Kato, Yusuke Takehana, Mitsuru Sakaizumi, Satoshi HamaguchiAbstract:A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
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Identification of the sex-determining locus in the Thai medaka, Oryzias minutillus
Cytogenetic and Genome Research, 2008Co-Authors: T Nagai, Yusuke Takehana, Satoshi Hamaguchi, Mitsuru SakaizumiAbstract:A sex-determining gene, DMY, which is comparable to the SRY gene in mammals, has been identified in the medaka, Oryzias Latipes. Although Oryzias curvinotus, a closely related species to O. Latipes also has DMY, this gene has not been found in other Oryzias fishes. It has recently been demonstrated that the sex chromosomes of Oryzias dancena and Oryzias hubbsi differ from those of O. Latipes and these species have XX/XY and ZZ/ZW systems, respectively. This may suggest that Oryzias species have evolved different sex-determining genes on different sex chromosomes. In the present study, we investigated the sex determination mechanism in Oryzias minutillus, which is closely related to O. dancena and O. hubbsi. Linkage analysis using 14 isolated sex-linked DNA markers showed that this species has an XX/XY sex determination system. These sex-linked markers were located on linkage group 8 of O. Latipes, suggesting that the sex chromosomes of O. minutillus are homologous to the autosomes of other Oryzias species. Furthermore, fluorescence in situ hybridization using a tightly sex-linked marker demonstrated that the XY sex chromosomes of O. minutillus and O. dancena were not homologous. These findings provide additional evidence for independent origins of sex chromosomes and sex-determining genes in these closely related species.
Yusuke Takehana - One of the best experts on this subject based on the ideXlab platform.
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The origin of the large metacentric chromosome pair in Chinese medaka ( Oryzias sinensis )
Ichthyological Research, 2012Co-Authors: Taijun Myosho, Yusuke Takehana, Tadashi Sato, Satoshi Hamaguchi, Mitsuru SakaizumiAbstract:Japanese medakas (Oryzias Latipes and Oryzias sakaizumii) have 48 chromosomes, while the Chinese medaka (Oryzias sinensis) has 46 chromosomes, including one pair of large metacentric chromosomes. Linkage analysis using O. sakaizumii and O. sinensis strains showed that DNA markers in linkage groups (LG) 11 and 13 were tightly linked. Centromeric genomic clones of LG 11 and 13 derived from an O. Latipes strain hybridized across the centromeres of the pair of large metacentric chromosomes in an O. sinensis strain. These results demonstrate that the large metacentric chromosome pair was derived from two pairs of acrocentric chromosomes (LG 11 and 13) through Robertsonian fusion.
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An autosomal locus controls sex reversal in interspecific XY hybrids of the medaka fishes
Heredity, 2011Co-Authors: Mariko Kato, Yusuke Takehana, Mitsuru Sakaizumi, Kiyoshi Naruse, Y Fukuda, Satoshi HamaguchiAbstract:Although the two medaka species Oryzias Latipes and O. curvinotus share the sex-determining gene Dmy, XY sex reversal occurs in interspecific hybridization between O. Latipes females of the Hd-rR inbred strain and O. curvinotus males. In this Hd-rR-curvinotus mating, all XX and XY hybrids developed as females. In this study, we used another O. Latipes inbred strain (HNI) for the mating, and found that 23% of XY hybrids developed as males, although all XX and the remaining XY hybrids developed as females. Linkage analysis using 236 XY hybrid males obtained from (Hd-rR × HNI) F1 females showed that a single major locus, Hybrid maleless (Hml), on autosomal linkage group 17, contributed to the strain difference in the XY sex reversal. Furthermore, we found that crossing females of a different O. Latipes inbred strain, HO4C, did not cause XY sex reversal in the interspecific hybrids, and that the XY hybrids from (Hd-rR × HO4C) F1 females showed a 1:1 sex ratio. XY hybrid males had the HO4C allele at sequence-tagged site loci around the Hml locus whereas XY females had the Hd-rR allele, confirming the strong contribution of this locus to XY sex reversal. Reverse transcriptase PCR analysis showed a reduced expression of Dmycurvinotus in XY fry of the Hd-rR-curvinotus hybrids at hatching. These results suggest that the Hd-rR allele at the Hml locus interfere with the function of Dmycurvinotus on a hybrid background, thus resulting in XY sex reversal.
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A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
Heredity, 2009Co-Authors: Mariko Kato, Yusuke Takehana, Mitsuru Sakaizumi, Satoshi HamaguchiAbstract:A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
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Identification of the sex-determining locus in the Thai medaka, Oryzias minutillus
Cytogenetic and Genome Research, 2008Co-Authors: T Nagai, Yusuke Takehana, Satoshi Hamaguchi, Mitsuru SakaizumiAbstract:A sex-determining gene, DMY, which is comparable to the SRY gene in mammals, has been identified in the medaka, Oryzias Latipes. Although Oryzias curvinotus, a closely related species to O. Latipes also has DMY, this gene has not been found in other Oryzias fishes. It has recently been demonstrated that the sex chromosomes of Oryzias dancena and Oryzias hubbsi differ from those of O. Latipes and these species have XX/XY and ZZ/ZW systems, respectively. This may suggest that Oryzias species have evolved different sex-determining genes on different sex chromosomes. In the present study, we investigated the sex determination mechanism in Oryzias minutillus, which is closely related to O. dancena and O. hubbsi. Linkage analysis using 14 isolated sex-linked DNA markers showed that this species has an XX/XY sex determination system. These sex-linked markers were located on linkage group 8 of O. Latipes, suggesting that the sex chromosomes of O. minutillus are homologous to the autosomes of other Oryzias species. Furthermore, fluorescence in situ hybridization using a tightly sex-linked marker demonstrated that the XY sex chromosomes of O. minutillus and O. dancena were not homologous. These findings provide additional evidence for independent origins of sex chromosomes and sex-determining genes in these closely related species.
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evidence for different origins of sex chromosomes in closely related oryzias fishes substitution of the master sex determining gene
Genetics, 2007Co-Authors: Keita Tanaka, Yusuke Takehana, Kiyoshi Naruse, Satoshi Hamaguchi, Mitsuru SakaizumiAbstract:The medaka Oryzias Latipes and its two sister species, O. curvinotus and O. luzonensis, possess an XX–XY sex-determination system. The medaka sex-determining gene DMY has been identified on the orthologous Y chromosome [O. Latipes linkage group 1 (LG1)] of O. curvinotus. However, DMY has not been discovered in other Oryzias species. These results and molecular phylogeny suggest that DMY was generated recently [∼10 million years ago (MYA)] by gene duplication of DMRT1 in a common ancestor of O. Latipes and O. curvinotus. We identified seven sex-linked markers from O. luzonensis (sister species of O. curvinotus) and constructed a sex-linkage map. Surprisingly, all seven sex-linked markers were located on an autosomal linkage group (LG12) of O. Latipes. As suggested by the phylogenetic tree, the sex chromosomes of O. luzonensis should be “younger” than those of O. Latipes. In the lineage leading to O. luzonensis after separation from O. curvinotus ∼5 MYA, a novel sex-determining gene may have arisen and substituted for DMY. Oryzias species should provide a useful model for evolution of the master sex-determining gene and differentiation of sex chromosomes from autosomes.
Mariko Kato - One of the best experts on this subject based on the ideXlab platform.
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An autosomal locus controls sex reversal in interspecific XY hybrids of the medaka fishes
Heredity, 2011Co-Authors: Mariko Kato, Yusuke Takehana, Mitsuru Sakaizumi, Kiyoshi Naruse, Y Fukuda, Satoshi HamaguchiAbstract:Although the two medaka species Oryzias Latipes and O. curvinotus share the sex-determining gene Dmy, XY sex reversal occurs in interspecific hybridization between O. Latipes females of the Hd-rR inbred strain and O. curvinotus males. In this Hd-rR-curvinotus mating, all XX and XY hybrids developed as females. In this study, we used another O. Latipes inbred strain (HNI) for the mating, and found that 23% of XY hybrids developed as males, although all XX and the remaining XY hybrids developed as females. Linkage analysis using 236 XY hybrid males obtained from (Hd-rR × HNI) F1 females showed that a single major locus, Hybrid maleless (Hml), on autosomal linkage group 17, contributed to the strain difference in the XY sex reversal. Furthermore, we found that crossing females of a different O. Latipes inbred strain, HO4C, did not cause XY sex reversal in the interspecific hybrids, and that the XY hybrids from (Hd-rR × HO4C) F1 females showed a 1:1 sex ratio. XY hybrid males had the HO4C allele at sequence-tagged site loci around the Hml locus whereas XY females had the Hd-rR allele, confirming the strong contribution of this locus to XY sex reversal. Reverse transcriptase PCR analysis showed a reduced expression of Dmycurvinotus in XY fry of the Hd-rR-curvinotus hybrids at hatching. These results suggest that the Hd-rR allele at the Hml locus interfere with the function of Dmycurvinotus on a hybrid background, thus resulting in XY sex reversal.
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A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
Heredity, 2010Co-Authors: Mariko Kato, Mitsuru Sakaizumi, Y Takehana, S. HamaguchiAbstract:Oryzias Latipes and Oryzias curvinotus are closely related medaka species that have the common sex-determining gene, DMY, on their homologous Y chromosomes. We previously reported that sex-reversed XY females were produced in hybrids between O. curvinotus females and O. Latipes males (Hd-rR inbred strain). In this study we used HNI inbred strain males of O. Latipes for mating with O. curvinotus females, and found that all the XY hybrids developed as males. To map the factor responsible for this strain-specific XY sex reversal, O. curvinotus females were mated with two Y-congenic strains (HNI.Y^Hd-rR and Hd-rR.Y^HNI) and a recombinant congenic strain (Hd-rR.Y^HNI rr ). HNI.Y^Hd-rR produced sex-reversed females in the XY hybrids, whereas no sex-reversed females were obtained in the XY hybrids from Hd-rR.Y^HNI and Hd-rR.Y^HNI rr , demonstrating that a small region on the Y chromosome, which includes DMY , is responsible for the XY sex reversal. Sex-reversed hybrids were only produced in the presence of the Y-chromosomal region derived from the Hd-rR strain, suggesting that missense or regulatory mutations specific to the Hd-rR Y-chromosomal region induce the sex reversal.
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A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
Heredity, 2009Co-Authors: Mariko Kato, Yusuke Takehana, Mitsuru Sakaizumi, Satoshi HamaguchiAbstract:A sex-determining region on the Y chromosome controls the sex-reversal ratio in interspecific hybrids between Oryzias curvinotus females and Oryzias Latipes males
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Interspecific hybridization between Oryzias Latipes and Oryzias curvinotus causes XY sex reversal.
Journal of Experimental Zoology Part A: Comparative Experimental Biology, 2006Co-Authors: Ai Shinomiya, Mitsuru Sakaizumi, Miki Yaezawa, Mariko Kato, Satoshi HamaguchiAbstract:The teleost fish, Oryzias curvinotus, is a closely related species to the medaka, Oryzias Latipes, and both species have the DMY gene, which is required for male development in O. Latipes. It suggests that the molecular function of the DMY gene and the following molecular events of sex differentiation are conserved between these two species. In the present study, we obtained interspecific hybrids between O. curvinotus and O. Latipes and demonstrated sex-reversed XY females in the hybrids. The incidence of sex-reversed females in F1 XY hybrids between O. curvinotus females and O. Latipes males, and hybrids between O. Latipes females and O. curvinotus males were 21% and 100%, respectively. These results indicate that DMY does not always determine maleness in hybrid fish even though it is able to specify normal male development on its native genetic background and suggest that there are some differences between DMY Latipes and DMY curvinotus alleles. Appearance of XY females in F1 hybrids also suggests that an autosomal or X-liked gene(s) from the maternal species interferes in the function of the paternal DMY gene in the male-determining process of the hybrid fish. These hybrid fish would supply a new experimental approach for investigating the genetic and molecular pathway of testis determination and differentiation. J. Exp. Zool. 305A:890-896, 2006. r 2006 Wiley-Liss, Inc.
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Interspecific hybridization between Oryzias Latipes and Oryzias curvinotus causes XY sex reversal.
Journal of experimental zoology. Part A Comparative experimental biology, 2006Co-Authors: Ai Shinomiya, Mitsuru Sakaizumi, Miki Yaezawa, Mariko Kato, Satoshi HamaguchiAbstract:The teleost fish, Oryzias curvinotus, is a closely related species to the medaka, Oryzias Latipes, and both species have the DMY gene, which is required for male development in O. Latipes. It suggests that the molecular function of the DMY gene and the following molecular events of sex differentiation are conserved between these two species. In the present study, we obtained interspecific hybrids between O. curvinotus and O. Latipes and demonstrated sex-reversed XY females in the hybrids. The incidence of sex-reversed females in F1 XY hybrids between O. curvinotus females and O. Latipes males, and hybrids between O. Latipes females and O. curvinotus males were 21% and 100%, respectively. These results indicate that DMY does not always determine maleness in hybrid fish even though it is able to specify normal male development on its native genetic background and suggest that there are some differences between DMY(Latipes) and DMY(curvinotus) alleles. Appearance of XY females in F1 hybrids also suggests that an autosomal or X-liked gene(s) from the maternal species interferes in the function of the paternal DMY gene in the male-determining process of the hybrid fish. These hybrid fish would supply a new experimental approach for investigating the genetic and molecular pathway of testis determination and differentiation.
Pungpung Hwang - One of the best experts on this subject based on the ideXlab platform.
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differential expression of branchial na k atpase of two medaka species oryzias Latipes and oryzias dancena with different salinity tolerances acclimated to fresh water brackish water and seawater
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2008Co-Authors: Chaokai Kang, Shuchuan Tsai, Pungpung HwangAbstract:Abstract Previous studies on non-diadromous euryhaline teleosts introduced a hypothesis that the lowest level of gill Na + /K + -ATPase (NKA) activity occurs in the environments with salinity close to the primary natural habitats of the studied species. To provide more evidence of the hypothesis, two medaka species, Oryzias Latipes and O. dancena , whose primary natural habitats are fresh water (FW) and brackish water (BW) environments, respectively, were compared from levels of mRNA to cells in this study. The plasma osmolalities of O. Latipes and O. dancena were lowest in the FW individuals. The muscle water contents of O. Latipes decreased with elevated external salinities, but were constant among FW-, BW-, and seawater (SW)-acclimated O. dancena . Expression of NKA, the primary driving force of ion transporters in gill ionocytes, revealed different patterns in the two Oryzias species. The highest NKA α-subunit mRNA abundances were found in the gills of the SW O. Latipes and the FW O. dancena , respectively. The pattern of NKA activity and α-subunit protein abundance in the gills of O. Latipes revealed that the FW group was the lowest, while the pattern in O. dancena revealed that the BW group was the lowest. Immunohistochemical staining showed similar profiles of NKA immunoreactive (NKIR) cell activities (NKIR cell number × cell size) in the gills of these two species among FW, BW, and SW groups. Taken together, O. Latipes exhibited better hyposmoregulatory ability, while O. dancena exhibited better hyperosmoregulatory ability. Our results corresponding to the hypothesis indicated that the lowest branchial NKA activities of these two medaka species were found in the environments with salinities similar to their natural habitats.
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Differential expression of branchial Na+/K(+)-ATPase of two medaka species, Oryzias Latipes and Oryzias dancena, with different salinity tolerances acclimated to fresh water, brackish water and seawater.
Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 2008Co-Authors: Chaokai Kang, Shuchuan Tsai, Tsung-han Lee, Pungpung HwangAbstract:Abstract Previous studies on non-diadromous euryhaline teleosts introduced a hypothesis that the lowest level of gill Na + /K + -ATPase (NKA) activity occurs in the environments with salinity close to the primary natural habitats of the studied species. To provide more evidence of the hypothesis, two medaka species, Oryzias Latipes and O. dancena , whose primary natural habitats are fresh water (FW) and brackish water (BW) environments, respectively, were compared from levels of mRNA to cells in this study. The plasma osmolalities of O. Latipes and O. dancena were lowest in the FW individuals. The muscle water contents of O. Latipes decreased with elevated external salinities, but were constant among FW-, BW-, and seawater (SW)-acclimated O. dancena . Expression of NKA, the primary driving force of ion transporters in gill ionocytes, revealed different patterns in the two Oryzias species. The highest NKA α-subunit mRNA abundances were found in the gills of the SW O. Latipes and the FW O. dancena , respectively. The pattern of NKA activity and α-subunit protein abundance in the gills of O. Latipes revealed that the FW group was the lowest, while the pattern in O. dancena revealed that the BW group was the lowest. Immunohistochemical staining showed similar profiles of NKA immunoreactive (NKIR) cell activities (NKIR cell number × cell size) in the gills of these two species among FW, BW, and SW groups. Taken together, O. Latipes exhibited better hyposmoregulatory ability, while O. dancena exhibited better hyperosmoregulatory ability. Our results corresponding to the hypothesis indicated that the lowest branchial NKA activities of these two medaka species were found in the environments with salinities similar to their natural habitats.
