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Genomic analysis of the Pacific oyster (Crassostrea gigas) reveals possible conservation of vertebrate sex determination in a mollusc.

Zhang N, Xu F, Guo X - G3 (Bethesda) (2014)

Bottom Line: Our analysis identified or confirmed novel homologs in the oyster of key sex-determining genes (SoxH or Sry-like and FoxL2) that were thought to be vertebrate-specific.Our findings plus previous results suggest that key vertebrate sex-determining genes such as Sry and FoxL2 may not be inventions of vertebrates.The presence of such genes in a mollusc with expression profiles consistent with expected roles in sex determination suggest that sex determination may be deeply conserved in animals, despite rapid evolution of the regulatory pathways that in C. gigas may involve both genetic and environmental factors.

View Article: PubMed Central - PubMed

Affiliation: National & Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong 266071, China Haskin Shellfish Research Laboratory, Institute of Marine and Coastal Sciences, Rutgers University, Port Norris, New Jersey 08349 University of Chinese Academy of Sciences, Beijing 100049, China.

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SoxE and SoxH genes identified in C. gigas and their expression profile. (A) Alignment of HMG domains of CgSoxE, CgSoxH, and homologs from selected vertebrates. (B) Phylogenetic tree of protein sequences of CgSoxE, CgSoxH, and selected genes. (C) Expression profile of CgSoxE and CgSoxH in adult organs of C. gigas with standard deviation as error bars (n = 3). Species names are abbreviated as Cg for Crassostrea gigas, Dm for Drosophila melanogaster, Dr for Danio rerio, Mm for Mus musculus, and Hs for Homo sapiens. Numbers in the tree represent bootstrap values. Accession numbers: CgSoxE EKC31659.1, CgSoxH EKC38002.1, DmSox100B AAF57112.2, MmSry AAI11529.1, HsSry AFG33955.1, HsSox8 AAH31797.1, HsSox9 CAA86598.1, HsSox10 CAG30470.1, and HsSox30 BAA37146.1.
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fig2: SoxE and SoxH genes identified in C. gigas and their expression profile. (A) Alignment of HMG domains of CgSoxE, CgSoxH, and homologs from selected vertebrates. (B) Phylogenetic tree of protein sequences of CgSoxE, CgSoxH, and selected genes. (C) Expression profile of CgSoxE and CgSoxH in adult organs of C. gigas with standard deviation as error bars (n = 3). Species names are abbreviated as Cg for Crassostrea gigas, Dm for Drosophila melanogaster, Dr for Danio rerio, Mm for Mus musculus, and Hs for Homo sapiens. Numbers in the tree represent bootstrap values. Accession numbers: CgSoxE EKC31659.1, CgSoxH EKC38002.1, DmSox100B AAF57112.2, MmSry AAI11529.1, HsSry AFG33955.1, HsSox8 AAH31797.1, HsSox9 CAA86598.1, HsSox10 CAG30470.1, and HsSox30 BAA37146.1.

Mentions: The C. gigas genome encodes 32 proteins containing the HMG domain, and 10 of them can be classified as Sox genes (Table 3). One of the oyster Sox genes (Cg22931) recently has been identified as a member of the SoxE family (Cg-SoxE) that includes the sex-determining Sox9 from mammals (Santerre et al. 2014). Its HMG domain shares high similarity (86.1%) to that of Sox8 and Sox9 in vertebrates (Figure 2, A and B). However, Cg-SoxE is probably not involved in sex determination. In Santerre et al.’s (2014) study, Cg-SoxE was expressed in both male and female gonads, higher at undifferentiated than mature stages. In our transcriptome data, it was mostly expressed in somatic organs (averaging 197 RPKM) and at gastrula stage (194 RPKM); its expression was lower in male (90 RPKM) and female (61 RPKM) gonads (Figure 2C). These results suggest that the primary function of Cg-SoxE may not be related to sex determination or differentiation in C. gigas.


Genomic analysis of the Pacific oyster (Crassostrea gigas) reveals possible conservation of vertebrate sex determination in a mollusc.

Zhang N, Xu F, Guo X - G3 (Bethesda) (2014)

SoxE and SoxH genes identified in C. gigas and their expression profile. (A) Alignment of HMG domains of CgSoxE, CgSoxH, and homologs from selected vertebrates. (B) Phylogenetic tree of protein sequences of CgSoxE, CgSoxH, and selected genes. (C) Expression profile of CgSoxE and CgSoxH in adult organs of C. gigas with standard deviation as error bars (n = 3). Species names are abbreviated as Cg for Crassostrea gigas, Dm for Drosophila melanogaster, Dr for Danio rerio, Mm for Mus musculus, and Hs for Homo sapiens. Numbers in the tree represent bootstrap values. Accession numbers: CgSoxE EKC31659.1, CgSoxH EKC38002.1, DmSox100B AAF57112.2, MmSry AAI11529.1, HsSry AFG33955.1, HsSox8 AAH31797.1, HsSox9 CAA86598.1, HsSox10 CAG30470.1, and HsSox30 BAA37146.1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4232546&req=5

fig2: SoxE and SoxH genes identified in C. gigas and their expression profile. (A) Alignment of HMG domains of CgSoxE, CgSoxH, and homologs from selected vertebrates. (B) Phylogenetic tree of protein sequences of CgSoxE, CgSoxH, and selected genes. (C) Expression profile of CgSoxE and CgSoxH in adult organs of C. gigas with standard deviation as error bars (n = 3). Species names are abbreviated as Cg for Crassostrea gigas, Dm for Drosophila melanogaster, Dr for Danio rerio, Mm for Mus musculus, and Hs for Homo sapiens. Numbers in the tree represent bootstrap values. Accession numbers: CgSoxE EKC31659.1, CgSoxH EKC38002.1, DmSox100B AAF57112.2, MmSry AAI11529.1, HsSry AFG33955.1, HsSox8 AAH31797.1, HsSox9 CAA86598.1, HsSox10 CAG30470.1, and HsSox30 BAA37146.1.
Mentions: The C. gigas genome encodes 32 proteins containing the HMG domain, and 10 of them can be classified as Sox genes (Table 3). One of the oyster Sox genes (Cg22931) recently has been identified as a member of the SoxE family (Cg-SoxE) that includes the sex-determining Sox9 from mammals (Santerre et al. 2014). Its HMG domain shares high similarity (86.1%) to that of Sox8 and Sox9 in vertebrates (Figure 2, A and B). However, Cg-SoxE is probably not involved in sex determination. In Santerre et al.’s (2014) study, Cg-SoxE was expressed in both male and female gonads, higher at undifferentiated than mature stages. In our transcriptome data, it was mostly expressed in somatic organs (averaging 197 RPKM) and at gastrula stage (194 RPKM); its expression was lower in male (90 RPKM) and female (61 RPKM) gonads (Figure 2C). These results suggest that the primary function of Cg-SoxE may not be related to sex determination or differentiation in C. gigas.

Bottom Line: Our analysis identified or confirmed novel homologs in the oyster of key sex-determining genes (SoxH or Sry-like and FoxL2) that were thought to be vertebrate-specific.Our findings plus previous results suggest that key vertebrate sex-determining genes such as Sry and FoxL2 may not be inventions of vertebrates.The presence of such genes in a mollusc with expression profiles consistent with expected roles in sex determination suggest that sex determination may be deeply conserved in animals, despite rapid evolution of the regulatory pathways that in C. gigas may involve both genetic and environmental factors.

View Article: PubMed Central - PubMed

Affiliation: National & Local Joint Engineering Laboratory of Ecological Mariculture, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong 266071, China Haskin Shellfish Research Laboratory, Institute of Marine and Coastal Sciences, Rutgers University, Port Norris, New Jersey 08349 University of Chinese Academy of Sciences, Beijing 100049, China.

Show MeSH
Related in: MedlinePlus