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Kuhl H, Euclide PT, Klopp C, Cabau C, Zahm M, Lopez-Roques C, Iampietro C, Kuchly C, Donnadieu C, Feron R, Parrinello H, Poncet C, Jaffrelo L, Confolent C, Wen M, Herpin A, Jouanno E, Bestin A, Haffray P, Morvezen R, de Almeida TR, Lecocq T, Schaerlinger B, Chardard D, Żarski D, Larson WA, Postlethwait JH, Timirkhanov S, Kloas W, Wuertz S, Stöck M, Guiguen Y. Multi-genome comparisons reveal gain-and-loss evolution of anti-Mullerian hormone receptor type 2 as a candidate master sex-determining gene in Percidae. BMC Biol 2024; 22:141. [PMID: 38926709 PMCID: PMC11209984 DOI: 10.1186/s12915-024-01935-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024] Open
Abstract
BACKGROUND The Percidae family comprises many fish species of major importance for aquaculture and fisheries. Based on three new chromosome-scale assemblies in Perca fluviatilis, Perca schrenkii, and Sander vitreus along with additional percid fish reference genomes, we provide an evolutionary and comparative genomic analysis of their sex-determination systems. RESULTS We explored the fate of a duplicated anti-Mullerian hormone receptor type-2 gene (amhr2bY), previously suggested to be the master sex-determining (MSD) gene in P. flavescens. Phylogenetically related and structurally similar amhr2 duplicates (amhr2b) were found in P. schrenkii and Sander lucioperca, potentially dating this duplication event to their last common ancestor around 19-27 Mya. In P. fluviatilis and S. vitreus, this amhr2b duplicate has been likely lost while it was subject to amplification in S. lucioperca. Analyses of the amhr2b locus in P. schrenkii suggest that this duplication could be also male-specific as it is in P. flavescens. In P. fluviatilis, a relatively small (100 kb) non-recombinant sex-determining region (SDR) was characterized on chromosome 18 using population-genomics approaches. This SDR is characterized by many male-specific single-nucleotide variations (SNVs) and no large duplication/insertion event, suggesting that P. fluviatilis has a male heterogametic sex-determination system (XX/XY), generated by allelic diversification. This SDR contains six annotated genes, including three (c18h1orf198, hsdl1, tbc1d32) with higher expression in the testis than in the ovary. CONCLUSIONS Together, our results provide a new example of the highly dynamic sex chromosome turnover in teleosts and provide new genomic resources for Percidae, including sex-genotyping tools for all three known Perca species.
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Affiliation(s)
- Heiner Kuhl
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries - IGB (Forschungsverbund Berlin), Müggelseedamm 301/310, D-12587, Berlin, Germany.
| | - Peter T Euclide
- Department of Forestry and Natural Resources | Illinois-Indiana Sea Grant, Purdue University, West Lafayette, USA
| | - Christophe Klopp
- Sigenae, Plateforme Bioinformatique, Genotoul, BioinfoMics, UR875 Biométrie et Intelligence Artificielle, INRAE, Castanet-Tolosan, France
| | - Cédric Cabau
- Sigenae, GenPhySE, Université de Toulouse, INRAE, ENVT, Castanet-Tolosan, France
| | - Margot Zahm
- Sigenae, Plateforme Bioinformatique, Genotoul, BioinfoMics, UR875 Biométrie et Intelligence Artificielle, INRAE, Castanet-Tolosan, France
| | | | | | - Claire Kuchly
- INRAE, US 1426, GeT-PlaGe, Genotoul, Castanet-Tolosan, France
| | | | - Romain Feron
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Hugues Parrinello
- Montpellier GenomiX (MGX), c/o Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Charles Poncet
- GDEC Gentyane, INRAE, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Lydia Jaffrelo
- GDEC Gentyane, INRAE, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Carole Confolent
- GDEC Gentyane, INRAE, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Ming Wen
- INRAE, LPGP, 35000, Rennes, France
- State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, China
| | | | | | - Anastasia Bestin
- SYSAAF, Station INRAE-LPGP, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Pierrick Haffray
- SYSAAF, Station INRAE-LPGP, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Romain Morvezen
- SYSAAF, Station INRAE-LPGP, Campus de Beaulieu, 35042, Rennes Cedex, France
| | | | | | | | | | - Daniel Żarski
- Department of Gamete and Embryo Biology, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, ul. Tuwima 10, 10-748, Olsztyn, Poland
| | - Wesley A Larson
- National Oceanographic and Atmospheric Administration, National Marine Fisheries Service, Alaska Fisheries Science Center, 17109 Point Lena Loop Road, Auke Bay LaboratoriesJuneau, AK, 99801, USA
| | | | | | - Werner Kloas
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries - IGB (Forschungsverbund Berlin), Müggelseedamm 301/310, D-12587, Berlin, Germany
| | - Sven Wuertz
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries - IGB (Forschungsverbund Berlin), Müggelseedamm 301/310, D-12587, Berlin, Germany
| | - Matthias Stöck
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries - IGB (Forschungsverbund Berlin), Müggelseedamm 301/310, D-12587, Berlin, Germany
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Kuhl H, Euclide PT, Klopp C, Cabau C, Zahm M, Roques C, Iampietro C, Kuchly C, Donnadieu C, Feron R, Parrinello H, Poncet C, Jaffrelo L, Confolent C, Wen M, Herpin A, Jouanno E, Bestin A, Haffray P, Morvezen R, de Almeida TR, Lecocq T, Schaerlinger B, Chardard D, Żarski D, Larson W, Postlethwait JH, Timirkhanov S, Kloas W, Wuertz S, Stöck M, Guiguen Y. Multi-genome comparisons reveal gain-and-loss evolution of the anti-Mullerian hormone receptor type 2 gene, an old master sex determining gene, in Percidae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.566804. [PMID: 38014084 PMCID: PMC10680665 DOI: 10.1101/2023.11.13.566804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The Percidae family comprises many fish species of major importance for aquaculture and fisheries. Based on three new chromosome-scale assemblies in Perca fluviatilis , Perca schrenkii and Sander vitreus along with additional percid fish reference genomes, we provide an evolutionary and comparative genomic analysis of their sex-determination systems. We explored the fate of a duplicated anti-Mullerian hormone receptor type-2 gene ( amhr2bY ), previously suggested to be the master sex determining (MSD) gene in P. flavescens . Phylogenetically related and structurally similar a mhr2 duplications ( amhr2b ) were found in P. schrenkii and Sander lucioperca , potentially dating this duplication event to their last common ancestor around 19-27 Mya. In P. fluviatilis and S. vitreus , this amhr2b duplicate has been lost while it was subject to amplification in S. lucioperca . Analyses of the amhr2b locus in P. schrenkii suggest that this duplication could be also male-specific as it is in P. flavescens . In P. fluviatilis , a relatively small (100 kb) non-recombinant sex-determining region (SDR) was characterized on chromosome-18 using population-genomics approaches. This SDR is characterized by many male-specific single-nucleotide variants (SNVs) and no large duplication/insertion event, suggesting that P. fluviatilis has a male heterogametic sex determination system (XX/XY), generated by allelic diversification. This SDR contains six annotated genes, including three ( c18h1orf198 , hsdl1 , tbc1d32 ) with higher expression in testis than ovary. Together, our results provide a new example of the highly dynamic sex chromosome turnover in teleosts and provide new genomic resources for Percidae, including sex-genotyping tools for all three known Perca species.
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Djihinto O, Saizonou HD, Djogbenou LS. Single nucleotide polymorphism (SNP) in the doublesex ( dsx) gene splice sites and relevance for its alternative splicing in the malaria vector Anopheles gambiae. Wellcome Open Res 2023; 7:31. [PMID: 37546169 PMCID: PMC10397894 DOI: 10.12688/wellcomeopenres.17572.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2023] [Indexed: 08/08/2023] Open
Abstract
Background: Malaria burden continues to be significant in tropical regions, and conventional vector control methods are faced with challenges such as insecticide resistance. To overcome these challenges, additional vector control interventions are vital and include modern genetic approaches as well as classical methods like the sterile insect technique (SIT). In the major human malaria vector Anopheles gambiae, a candidate gene favourable for sterility induction is the doublesex ( dsx) gene, involved in mosquitos' somatic sexually dimorphic traits determination. However, the pathways that trigger the signal of dsx gene exon skipping alternative splicing mechanism in anopheline mosquitoes are not well characterized. This study aims to screen the An. gambiae dsx gene splice site sequences for single-nucleotide polymorphisms (SNPs) that could be critical to its alternative splicing. Methods: Variant annotation data from Ag1000G project phase 2 was analysed, in order to identify splice-relevant SNPs within acceptor and donor splice sites of the An. gambiae dsx gene ( Agdsx). Results: SNPs were found in both donor and acceptor sites of the Agdsx. No splice-relevant SNPs were identified in the female-specific intron 4 acceptor site and the corresponding region in males. Two SNPs (rs48712947, rs48712962) were found in the female-specific donor site of exon 5. They were not specific to either males or females as the rs48712947 was found in female mosquitoes from Cameroon, and in both males and females from Burkina Faso. In the other splice sites, the intron 3 acceptor site carried the greatest abundance of SNPs. Conclusions: There were no gender association between the identified SNPs and the random distribution of these SNPs in mosquito populations. The SNPs in Agdsx splice sites are not critical for the alternative splicing. Other molecular mechanisms should be considered and investigated.
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Affiliation(s)
- Oswald Djihinto
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, Abomey-Calavi, 01BP526 Cotonou, Benin
| | - Helga D.M. Saizonou
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, Abomey-Calavi, 01BP526 Cotonou, Benin
| | - Luc S. Djogbenou
- Tropical Infectious Diseases Research Centre (TIDRC), University of Abomey-Calavi, Abomey-Calavi, 01BP526 Cotonou, Benin
- Institut Régional de Santé Publique, University of Abomey-Calavi, Ouidah, BP 384 Ouidah, Benin
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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Master-Key Regulators of Sex Determination in Fish and Other Vertebrates-A Review. Int J Mol Sci 2023; 24:ijms24032468. [PMID: 36768795 PMCID: PMC9917144 DOI: 10.3390/ijms24032468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/12/2023] [Accepted: 01/25/2023] [Indexed: 02/01/2023] Open
Abstract
In vertebrates, mainly single genes with an allele ratio of 1:1 trigger sex-determination (SD), leading to initial equal sex-ratios. Such genes are designated master-key regulators (MKRs) and are frequently associated with DNA structural variations, such as copy-number variation and null-alleles. Most MKR knowledge comes from fish, especially cichlids, which serve as a genetic model for SD. We list 14 MKRs, of which dmrt1 has been identified in taxonomically distant species such as birds and fish. The identification of MKRs with known involvement in SD, such as amh and fshr, indicates that a common network drives SD. We illustrate a network that affects estrogen/androgen equilibrium, suggesting that structural variation may exert over-expression of the gene and thus form an MKR. However, the reason why certain factors constitute MKRs, whereas others do not is unclear. The limited number of conserved MKRs suggests that their heterologous sequences could be used as targets in future searches for MKRs of additional species. Sex-specific mortality, sex reversal, the role of temperature in SD, and multigenic SD are examined, claiming that these phenomena are often consequences of artificial hybridization. We discuss the essentiality of taxonomic authentication of species to validate purebred origin before MKR searches.
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Djihinto O, Saizonou HD, Djogbenou LS. Single nucleotide polymorphism (SNP) in the doublesex (dsx) gene splice sites and relevance for its alternative splicing in the malaria vector Anopheles gambiae. Wellcome Open Res 2022. [DOI: 10.12688/wellcomeopenres.17572.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Background: Malaria burden continues to be significant in tropical regions, and conventional vector control methods are faced with challenges such as insecticide resistance. To overcome these challenges, additional vector control interventions are vital and include modern genetic approaches as well as classical methods like the sterile insect technique (SIT). In the major human malaria vector Anopheles gambiae, a candidate gene favourable for sterility induction is the doublesex (dsx) gene, involved in mosquitos’ somatic sexually dimorphic traits determination. However, the pathways that trigger the signal of dsx gene exon skipping alternative splicing mechanism in anopheline mosquitoes are not well characterized. This study aims to screen the An. gambiae dsx gene splice site sequences for single-nucleotide polymorphisms (SNPs) that could be critical to its alternative splicing. Methods: Variant annotation data from Ag1000G project phase 2 was analysed, in order to identify splice-relevant SNPs within acceptor and donor splice sites of the An. gambiae dsx gene (Agdsx). Results: SNPs were found in both donor and acceptor sites of the Agdsx. No splice-relevant SNPs were identified in the female-specific intron 4 acceptor site and the corresponding region in males. Two SNPs (rs48712947, rs48712962) were found in the female-specific donor site of exon 5. They were not specific to either males or females as the rs48712947 was found in female mosquitoes from Cameroon, and in both males and females from Burkina Faso. In the other splice sites, the intron 3 acceptor site carried the greatest abundance of SNPs. Conclusions: There were no gender association between the identified SNPs and the random distribution of these SNPs in mosquito populations. The SNPs in Agdsx splice sites are not critical for the alternative splicing. Other molecular mechanisms should be considered and investigated.
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Identification and Characterization of Sex-Biased miRNAs in the Golden Pompano ( Trachinotus blochii). Animals (Basel) 2022; 12:ani12233342. [PMID: 36496865 PMCID: PMC9739008 DOI: 10.3390/ani12233342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/25/2022] [Accepted: 11/25/2022] [Indexed: 12/05/2022] Open
Abstract
The golden pompano (Trachinotus blochii) is a marine fish of considerable commercial importance in China. It shows notable sexual size dimorphism; the growth rate of females is faster than that of males. Therefore, sex-biased research is of great importance in T. blochii breeding. However, there have been few studies on sex differentiation and mechanisms underlying sex determination in T. blochii. MicroRNAs (miRNAs) play crucial roles in sex differentiation and determination in animals. However, limited miRNA data are available on fish. In this study, two small RNA libraries prepared from the gonads of T. blochii were constructed and sequenced. The RNA-seq analysis yielded 1366 known and 69 novel miRNAs with 289 significantly differentially expressed miRNAs (p < 0.05). Gene ontology (GO) analysis confirmed that the TFIIA transcription factor complex (GO: 0005672) was the most significantly enriched GO term. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the differentially expressed miRNAs and target genes were mainly related to sex determination and gonadal developmental signaling pathways, specifically the Wnt signaling pathway, MAPK signaling pathway, and steroid biosynthetic pathway. MiRNA-mRNA co-expression network analysis strongly suggested a role for sex-biased miRNAs in sex determination/differentiation and gonadal development. For example, gata4, foxo3, wt1, and sf1 genes were found to be regulated by bta-miR-2898; esr2 and foxo3 by novel_176, and ar by oar-let-7b. Quantitative real-time polymerase chain reaction analysis of selected mRNAs and miRNAs validated the integrated analysis. This study established a set of sex-biased miRNAs that are potential regulatory factors in gonadal development in T. blochii. These results provide new insight into the function of miRNAs in sex differentiation and determination in T. blochii and highlight some key miRNAs for future studies.
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Sun C, Shabbir S, Wang W, Gao Y, Ge C, Lin Q. Transcriptome Analysis Revealed Genes Related to γ-Irradiation Induced Emergence Failure in Third-Instar Larvae of Bactrocera dorsalis. INSECTS 2022; 13:1017. [PMID: 36354841 PMCID: PMC9699437 DOI: 10.3390/insects13111017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/06/2022] [Accepted: 11/02/2022] [Indexed: 06/16/2023]
Abstract
The oriental fruit fly is a polyphagous and highly invasive economically important pest in the world. We proposed the hypothesis that radiation treatment influence RNA expression in the larvae and leads to emergence failure. Therefore, transcriptome analyses of third-instar larvae of B. dorsalis ionizing, irradiated with 60Co-γ at 116Gy, were conducted and compared with the controls; a total of 608 DEGs were identified, including 348 up-regulated genes and 260 down-regulated ones. In addition, 130 SNPs in 125 unigenes were identified. For the DEGs, the most significantly enriched GO item was hemolymph coagulation, and some of the enriched pathways were involved in digestive processes. The subsequent validation experiment confirmed the differential expression of six genes, including sqd, ENPEP, Jhe, mth, Notch, and Ugt. Additionally, the 3401:G->A SNP in the Notch gene was also successfully validated. According to previous research, this was the first comparative transcriptome study to discover the candidate genes involved in insect molt to pupae. These results not only deepen our understanding of the emerging mechanism of B. dorsalis but also provide new insights into the research of biomarkers for quarantine insect treatment with the appropriate dose of radiation.
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Affiliation(s)
- Chao Sun
- Guizhou Medical University (GMU), Guiyang 550000, China
| | - Samina Shabbir
- Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou 510640, China
| | - Wenxiang Wang
- Zanyu Technology Group Co., Ltd., Hangzhou 310000, China
| | - Yan Gao
- Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou 510640, China
| | - Cuicui Ge
- Zhejiang Gongzheng Testing Centre Co., Ltd., Hangzhou 310000, China
| | - Qingsheng Lin
- Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou 510640, China
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Li XY, Mei J, Ge CT, Liu XL, Gui JF. Sex determination mechanisms and sex control approaches in aquaculture animals. SCIENCE CHINA. LIFE SCIENCES 2022; 65:1091-1122. [PMID: 35583710 DOI: 10.1007/s11427-021-2075-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/14/2022] [Indexed: 01/21/2023]
Abstract
Aquaculture is one of the most efficient modes of animal protein production and plays an important role in global food security. Aquaculture animals exhibit extraordinarily diverse sexual phenotypes and underlying mechanisms, providing an ideal system to perform sex determination research, one of the important areas in life science. Moreover, sex is also one of the most valuable traits because sexual dimorphism in growth, size, and other economic characteristics commonly exist in aquaculture animals. Here, we synthesize current knowledge of sex determination mechanisms, sex chromosome evolution, reproduction strategies, and sexual dimorphism, and also review several approaches for sex control in aquaculture animals, including artificial gynogenesis, application of sex-specific or sex chromosome-linked markers, artificial sex reversal, as well as gene editing. We anticipate that better understanding of sex determination mechanisms and innovation of sex control approaches will facilitate sustainable development of aquaculture.
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Affiliation(s)
- Xi-Yin Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Hubei Hongshan Laboratory, The Innovative Academy of Seed Design, Institute of Hydrobiology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Wuhan, 430072, China
| | - Jie Mei
- College of Fisheries, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chu-Tian Ge
- College of Biological and Environmental Sciences, Zhejiang Wanli University, Ningbo, 315100, China
| | - Xiao-Li Liu
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380, China
| | - Jian-Fang Gui
- State Key Laboratory of Freshwater Ecology and Biotechnology, Hubei Hongshan Laboratory, The Innovative Academy of Seed Design, Institute of Hydrobiology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Wuhan, 430072, China.
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Curzon AY, Shirak A, Meerson A, Degani G, Hurvitz A, Ben-Naim N, Domovitz R, Ron M, Seroussi E. Cross-species conservation of a transposase-linked element enables genetic sexing of commercial populations of Russian sturgeon (Acipenser gueldenstaedtii). Anim Genet 2022; 53:441-446. [PMID: 35288964 PMCID: PMC9311079 DOI: 10.1111/age.13188] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/24/2022] [Accepted: 02/28/2022] [Indexed: 12/01/2022]
Abstract
All‐female culture of sturgeon is essential for efficient caviar production. However, Russian sturgeon (Acipenser gueldenstaedtii) does not exhibit external sexual dimorphism, and therefore, commercial farms apply gonadal endoscopy or ultrasound at the earliest age of 4–5 years to separate the sexes, with ~90% accuracy. Recently, a dominant genomic marker (AllWSEX2) has been found with association to femaleness in sturgeons. We developed a duplex PCR (dAllWSEX2) with the adjacent bmp7 gene as an internal control, to validate an effective PCR. Robust amplification of control fragments was observed for all samples of our commercial A. gueldenstaedtii stock (n = 337). The dAllWSEX2 assay was significantly associated with sex (n = 43, p < 1.6 × 10−8), yet four (18%) of the endoscopy‐determined females were genetic males. To examine whether some females display a male genetic profile, we tested 96 egg‐producing females, which were all verified as genetic females, indicating that the observed mismatches may be attributed to wrong sexing by endoscopy. Application of dAllWSEX2 on 100 7‐month‐old fish showed no sex‐dependent differences in body weight, indicating that weighing is not an applicable tool for sorting females at a young age. Sanger sequencing of the bmp7 fragment revealed octaploidy and sex‐independent variation, suggesting that the critical sex‐determining region harboring AllWSEX2 is small. In keeping with a model of a single‐ploidy encoding female determination, AllWSEX2 showed no variation despite being a transposase‐linked repetitive element. Cross‐species conservation of AllWSEX2, and absence of annotated sex‐determination genes in this region suggests that, in sturgeons, the sex‐determining mechanism is different from mechanisms identified in other fish.
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Affiliation(s)
- Arie Y Curzon
- Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon, Israel.,Robert H. Smith Faculty of Agriculture Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Andrey Shirak
- Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon, Israel
| | - Ari Meerson
- MIGAL-Galilee Technology Center, Kiryat Shmona, Israel.,School of Science and Technology, Tel-Hai Academic College, Galilee, Israel
| | - Gad Degani
- MIGAL-Galilee Technology Center, Kiryat Shmona, Israel.,School of Science and Technology, Tel-Hai Academic College, Galilee, Israel
| | - Avshalom Hurvitz
- Caviar Galilee Agricultural Cooperative Society Ltd., Kibbutz Dan, Israel
| | - Naama Ben-Naim
- Caviar Galilee Agricultural Cooperative Society Ltd., Kibbutz Dan, Israel
| | - Roee Domovitz
- Caviar Galilee Agricultural Cooperative Society Ltd., Kibbutz Dan, Israel
| | - Micha Ron
- Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon, Israel
| | - Eyal Seroussi
- Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon, Israel
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