Expression profiles of Dax1, Dmrt1, and Sox9 during temperature sex determination in gonads of the sea turtle Lepidochelys olivacea

The sex of sea turtles is determined by temperature during egg incubation. Thus, climate change affects the sex ratio, exacerbating their vulnerability to extinction. Understanding spatiotemporal effects of temperature on sex determination at the gonadal level may facilitate the design of strategies to mitigate the effects of global warming. Here, we used qRT-PCR and immunofluorescence to analyze the spatiotemporal expression of Dmrt1 and Foxl2 in developing gonads of Lepidochelys olivacea incubated at male-producing temperature (MPT, 26°C) or female-producing temperature (FPT, 33°C). Although both transcription factors are expressed in bipotential gonads up to stage 25, the timing of their sexually dimorphic regulation differs. Whereas the dimorphic expression of Dmrt1 protein initiates at stage 24, Foxl2 protein was expressed specifically in females at stage 25. Interestingly, whereas Dmrt1 colocalizes with Sox9 in cell nuclei of primary medullary cords to form the testis cords, Foxl2 protein is first detected in Sox9-negative cells of primary medullary cords, prior to its substantial expression in the ovarian cortex. Thus, results suggest that the temperature-dependent regulation of sexual pathways is stochastic among the cells of primary medullary cords in undifferentiated bipotential gonads of the olive ridley.

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Dimorphic DNA methylation during temperature-dependent sex determination in the sea turtle Lepidochelys olivacea

General and Comparative Endocrinology ◽

10.1016/j.ygcen.2016.06.026 ◽

2016 ◽

Vol 236 ◽

pp. 35-41 ◽

Cited By ~ 15

Author(s):

Daniela Venegas ◽

Alejandro Marmolejo-Valencia ◽

Christian Valdes-Quezada ◽

Tzipe Govenzensky ◽

Félix Recillas-Targa ◽

...

Keyword(s):

Dna Methylation ◽

Sex Determination ◽

Sea Turtle ◽

Temperature Dependent ◽

Lepidochelys Olivacea

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Exogenous estradiol alters gonadal growth and timing of temperature sex determination in gonads of sea turtle

Developmental Biology ◽

10.1016/j.ydbio.2015.05.022 ◽

2015 ◽

Vol 408 (1) ◽

pp. 79-89 ◽

Cited By ~ 8

Author(s):

Verónica Díaz-Hernández ◽

Alejandro Marmolejo-Valencia ◽

Horacio Merchant-Larios

Keyword(s):

Sex Determination ◽

Sea Turtle ◽

Gonadal Growth

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Chelonicola and Poulinea, two new gomphonemoid diatom genera (Bacillariophyta) living on marine turtles from Costa Rica

Phytotaxa ◽

10.11646/phytotaxa.233.3.2 ◽

2015 ◽

Vol 233 (3) ◽

pp. 236 ◽

Cited By ~ 21

Author(s):

Roksana Majewska ◽

J. P. Kociolek ◽

Evan W. Thomas ◽

Mario De Stefano ◽

Mario Santoro ◽

...

Keyword(s):

Costa Rica ◽

Marine Mammals ◽

Sea Turtles ◽

Sea Turtle ◽

New Genera ◽

Olive Ridley ◽

Lepidochelys Olivacea ◽

Marine Turtles ◽

The Family ◽

Long Time

Marine mammals such as whales and dolphins have been known for a long time to host a very specific epizoic community on their skin. Less known however is the presence of a similar community on the carapaces of sea turtles. The present study is the first describing new taxa inhabiting sea turtle carapaces. Samples, collected from nesting olive ridley sea turtles (Lepidochelys olivacea) on Ostional Beach (Costa Rica), were studied using light and scanning electron microscopy. Two unknown small-celled gomphonemoid taxa were analysed in more detail and are described as two new genera, closely related to other gomphonemoid genera with septate girdle bands, such as Tripterion, Cuneolus and Gomphoseptatum. Chelonicola Majewska, De Stefano & Van de Vijver gen. nov. has a flat valve face, uniseriate striae composed of more than three areolae, simple external raphe endings, internally a siliceous flap over the proximal raphe endings and lives on mucilaginous stalks. Poulinea Majewska, De Stefano & Van de Vijver gen. nov. has at least one concave valve, uniseriate striae composed of only two elongated areolae, external distal raphe endings covered by thickened siliceous flaps and lives attached to the substrate by a mucilaginous pad. Chelonicola costaricensis Majewska, De Stefano & Van de Vijver sp. nov. and Poulinea lepidochelicola Majewska, De Stefano & Van de Vijver sp. nov. can be separated based on stria structure, girdle structure composed of more than 10 copulae, raphe structure and general valve outline. A cladistics analysis of putative members of the Rhoicospheniaceae indicates that the family is polyphyletic. Chelonicola and Poulinea are sister taxa, and form a monophyletic group with Cuneolus and Tripterion, but are not closely related to Rhoicosphenia, or other genera previously assigned to this family. Features used to help diagnose the family such as symmetry and presence of septa and pseudosepta are homoplastic across the raphid diatom tree of life.

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Gonad Transcriptome Analysis of the Razor Clam (Sinonovacula constricta) Revealed Potential Sex-Related Genes

Frontiers in Marine Science ◽

10.3389/fmars.2021.725430 ◽

2021 ◽

Vol 8 ◽

Author(s):

Hanhan Yao ◽

Zhihua Lin ◽

Yinghui Dong ◽

Xianghui Kong ◽

Lin He ◽

...

Keyword(s):

Sex Determination ◽

Transcriptome Analysis ◽

Reference Genome ◽

Expression Profiles ◽

Rna Seq ◽

Sinonovacula Constricta ◽

Razor Clam ◽

Marine Bivalves ◽

Commercially Important ◽

The Western Pacific

The razor clam, Sinonovacula constricta is a commercially important bivalve in the western Pacific Ocean, yet little is known about the mechanisms of sex determination/differentiation and gametogenesis. In the present study, the comparative transcriptome analysis of adult gonads (female gonads and male gonads) was conducted to identify potential sex-related genes in S. constricta. The number of reads generated for each target library (three females and three males) ranged from 31,853,422 to 37,750,848, and 20,489,472 to 26,152,448 could be mapped to the reference genome of S. constricta (the map percentage ranging from 63.71 to 71.48%). A total of 8,497 genes were identified to be differentially expressed between the female and male gonads, of which 4,253 were female-biased (upregulated in females), and 4,244 were male-biased. Forty-five genes were identified as potential sex-related genes, including DmrtA2, Sox9, Fem-1b, and Fem-1c involved in sex determination/differentiation and Vg, CYP17A1, SOHLH2, and TSSK involved in gametogenesis. The expression profiles of 12 genes were validated by qRT-PCR, which further confirmed the reliability and accuracy of the RNA-Seq results. Our results provide basic information about the genes involved in sex determination/differentiation and gametogenesis, and pave the way for further studies on reproduction and breeding in S. constricta and other marine bivalves.

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