File(s) under permanent embargo
Sex biased expression of anti-Mullerian hormone (amh) gene in a live bearing fish, Gambusia holbrooki: evolutionary implications and potential role in sex differentiation
journal contributionposted on 2023-05-20, 01:16 authored by Tzu nin KwanTzu nin Kwan, Jawahar PATILJawahar PATIL
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.
Publication titleComparative Biochemistry and Physiology. Part B
Department/SchoolInstitute for Marine and Antarctic Studies
PublisherPergamon-Elsevier Science Ltd
Place of publicationThe Boulevard, Langford Lane, Kidlington, Oxford, England, Ox5 1Gb
Rights statementCopyright 2019 Elsevier Inc.
Socio-economic ObjectivesControl of pests, diseases and exotic species in fresh, ground and surface water