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Sex biased expression of anti-Mullerian hormone (amh) gene in a live bearing fish, Gambusia holbrooki: evolutionary implications and potential role in sex differentiation

Citation

Kwan, TN and Patil, JG, Sex biased expression of anti-Mullerian hormone (amh) gene in a live bearing fish, Gambusia holbrooki: evolutionary implications and potential role in sex differentiation, Comparative Biochemistry and Physiology. Part B, 231 pp. 59-66. ISSN 1096-4959 (2019) [Refereed Article]

Copyright Statement

Copyright 2019 Elsevier Inc.

DOI: doi:10.1016/j.cbpb.2019.02.004

Abstract

The amh, a member of transforming growth factor-β (TGF-β) family, is known to play a critical role in vertebrate male sex differentiation, with its paralogue/s evolving to determine sex in few heterogametic (XX/XY) teleosts. However, it remains relatively unexplored in the reproductively unique live bearing teleosts. Therefore, this study comparatively examined the structure and content of G. holbrooki amh as well as characterised its expression. A paralogous Y-specific amh (amhy) was not detected, suggesting an unlikely role in sex determination. Two transcripts (1.4 and 1.5 kb) were detected in adults: the larger (1.5 kb) retaining intron 5, coding for a truncated AMH-N and no TGF-β domain. The small (1.4 kb) transcript, had both domains intact and clustered with members of Poeciliidae. In contrast to other vertebrates, a higher conservation between the N- rather than the C- terminus of amh in Poeciliidae was observed, suggesting an adaptation that may be unique to live bearing teleosts. The amh expression was 6 times higher in brain of both sexes and testis compared with ovaries (p = .001). Intriguingly, female splenic tissues showed 10 times higher expression (p = .006) and such female bias splenic expression has not been reported in any teleosts. Ontogenic expression was 25 times higher in male embryos at gastrulation stage (p = .001), much earlier than those reported in egg-laying teleosts. Such heightened expression in male embryos suggests a repressive role associated with proliferation and migration of primordial germ cells (PGCs) that are known to occur earlier at blastulation in teleosts—potentially influencing gonadal fate.

Item Details

Item Type:Refereed Article
Keywords:reproduction, ontogeny, gene expression, blastulation, spleen, gonad
Research Division:Biological Sciences
Research Group:Genetics
Research Field:Developmental Genetics (incl. Sex Determination)
Objective Division:Environment
Objective Group:Control of Pests, Diseases and Exotic Species
Objective Field:Control of Pests, Diseases and Exotic Species in Fresh, Ground and Surface Water Environments
UTAS Author:Kwan, TN (Dr Tzu Kwan)
UTAS Author:Patil, JG (Dr Jawahar Patil)
ID Code:131082
Year Published:2019
Deposited By:Fisheries and Aquaculture
Deposited On:2019-02-28
Last Modified:2020-01-14
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