Investigating the molecular basis of sex reversal in sequential hermaphroditic fishes

Bluehead wrasse male with his harem of yellow females over corals
Investigating the molecular basis of sex reversal in sequential hermaphroditic fishes

Most plants and animals irreversibly differentiate becoming either males or females. However, in some groups, notably fishes, individuals begin life as one sex and reverse sex sometime later in response to social cues (sequential hermaphrodism).

Sex reversal in sequential hermaphrodites is complete,  entailing radical restructuring of the gonad, alterations in morphology, and modifications to behaviour.

The molecular basis of this stunning transformation is unknown, but is of intense interest, not only as a means to enhance our understanding of sex determination and differentiation, cellular commitment and tissue re engineering, but also as a spectacular example of phenotypic plasticity in response to environment.

Using the ubiquitous NZ spotty, together with two distant tropical relatives, the bluehead and three-spot wrasse, both leading models for sex reversal, we will undertake a series of experiments to determine the genetic pathway underlying this stunning transformation. We will undertake in the field ecological manipulations to produce a time series of samples taken during the process of sex reversal, and couple these with state-of-the-art gene expression analyses and comparative genomic approaches, to identify both the primary trigger and subsequent genetic cascade that results in female-male sex reversal in these fishes.

Currently involved in this project are Postdoctoral Fellows Dr. Chloé van der Burg and Dr. Kaj Kamstra, and also newly arrived PhD student Haylee Quertermous.

Collaborators

Dr. Erica Todd (Deakin University)

Dr. Alex Goikoetxea (Universitat Autònoma de Barcelona)

Assoc. Prof. John Godwin (North Carolina State University)

Ms Melissa Slane (North Carolina State University)

Prof. Masaru Nakamura (University of Ryukyus)

Dr Mark Lokman (University of Otago)

Dr Megan Wilson (University of Otago)

Dr Mik Black (University of Otago)

Dr. Simon Muncaster (BOP Polytechnic)

Dr. Ann Liu (University of Otago)