Prediction of the sex-determination gene in tunas (<i>Thunnus</i> fishes)

Nakamura, Yoji; Higuchi, Kentaro; Kumon, Kazunori; Yasuike, Motoshige; Takashi, Toshinori; Kobashi, Gén; Fujiwara, Atushi

doi:10.1101/2021.06.15.448492

Cited by 2 publications

(1 citation statement)

References 51 publications

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“…In this study, we resequenced and reassembled the PBT male genome using long-read sequencing technologies and examined the sex-associated regions using previously published data [ 17 ]. We have found a sex-associated gene that is paternally inherited and is involved in estrogen inactivation.…”

Section: Introductionmentioning

confidence: 99%

Prediction of the Sex-Associated Genomic Region in Tunas (Thunnus Fishes)

Nakamura

Higuchi

Kumon

et al. 2021

International Journal of Genomics

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Fish species have a variety of sex determination systems. Tunas (genus Thunnus) have an XY genetic sex determination system. However, the Y chromosome or responsible locus has not yet been identified in males. In a previous study, a female genome of Pacific bluefin tuna (T. orientalis) was sequenced, and candidates for sex-associated DNA polymorphisms were identified by a genome-wide association study using resequencing data. In the present study, we sequenced a male genome of Pacific bluefin tuna by long-read and linked-read sequencing technologies and explored male-specific loci through a comparison with the female genome. As a result, we found a unique region carrying the male-specific haplotype, where a homolog of estrogen sulfotransferase gene was predicted to be encoded. The genome-wide mapping of previously resequenced data indicated that, among the functionally annotated genes, only this gene, named sult1st6y, was paternally inherited in the males of Pacific bluefin tuna. We reviewed the RNA-seq data of southern bluefin tuna (T. maccoyii) in the public database and found that sult1st6y of southern bluefin tuna was expressed in all male testes, but absent or suppressed in the female ovary. Since estrogen sulfotransferase is responsible for the inactivation of estrogens, it is reasonable to assume that the expression of sult1st6y in gonad cells may inhibit female development, thereby inducing the individuals to become males. Thus, our results raise a promising hypothesis that sult1st6y is the sex determination gene in Thunnus fishes or at least functions at a crucial point in the sex-differentiation cascade.

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Section: Introductionmentioning

confidence: 99%

Prediction of the Sex-Associated Genomic Region in Tunas (Thunnus Fishes)

Nakamura

Higuchi

Kumon

et al. 2021

International Journal of Genomics

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Characterization of the sex determining region and development of a molecular sex identification method in a Salangid fish

Yang,

Li,

Xing

et al. 2024

BMC Genomics

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Background The short-snout icefish, Neosalanx brevirostris, a member of the Salangidae family, is an economically important fishery species in China. Understanding the mechanisms underlying sex determination in this species has crucial implications for conservation, ecology and evolution. Meanwhile, there is a shortage of rapid and cost-effective genetic methods for sex identification, which poses challenges in identifying the sex of immature individuals in sex determination mechanism studies and aquaculture breeding applications. Results Based on whole genome resequencing data, sex-specific loci and regions were found to be concentrated in a region on chromosome 2. All sex-specific loci exhibited excess heterozygosity in females and complete homozygosity in males. This sex determining region contains seven genes, including cytochrome P450 aromatase CYP19B, which is involved in steroidogenesis and is associated with 24 sex-specific loci and two W-deletions. A haploid female-specific sequence was identified as paralogous to a diploid sequence with a significant length difference, making it suitable for rapid and cost-effective genetic sex identification by traditional PCR and agarose gel electrophoresis, which were further validated in 24 females and 24 males with known phenotypic sexes. Conclusions Our results confirm that N.brevirostris exhibits a female heterogametic sex determination system (ZZ/ZW), with chromosome 2 identified as the putative sex chromosome containing a relatively small sex determining region (~ 48 Kb). The gene CYP19B is proposed as a candidate sex determining gene. Moreover, the development of PCR based method enables genetic sex identification at any developmental stage, thereby facilitating further studies on sex determination mechanisms and advancing aquaculture breeding applications for this species.

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Prediction of the sex-determination gene in tunas (Thunnus fishes)

Cited by 2 publications

References 51 publications

Prediction of the Sex-Associated Genomic Region in Tunas (Thunnus Fishes)

Prediction of the Sex-Associated Genomic Region in Tunas (Thunnus Fishes)

Characterization of the sex determining region and development of a molecular sex identification method in a Salangid fish

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