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The western mosquitofish (Gambusia affinis affinis): a new laboratory animal resource for the study of sexual dimorphism in neural circuits
Luis Rosario-Ortiz, BS, LAT1, Stephanie Rivera-Pabon2, Irma Torres-Vzquez, MS2,
Eduardo G. Ortiz-Perez2, Luzed Diaz-Perez, BS2, Loren Pesquera-Diaz2, Nydia L. Rivera-Rivera, BS2, Elymic Colon-Garcia2, Jose L. Serrano-Vlez, BS2 & Eduardo Rosa-Molinar, PhD1,2
The western mosquitofish (Gambusia affinis affinis) is a useful model for the study of sexual dimorphism and the neural circuits associated with sexual differentiation. This is largely because of its anal fin, which undergoes radical postnatal transformation in males. Understanding the neural mechanisms involved in this process may also help elucidate basic principles of the nervous system. The authors describe the mosquitofish as a model for research and present guidelines for the care and use of this species.
It is not always easy to identify the most suitable animal for research of fundamental principles in biology. For studies of the general mechanisms underlying nervous systems, it is useful to investigate animals with anatomical structures and nervous systems that have evolved to perform specific tasks15.
For 15 years our laboratory has focused on the sexually dimorphic western mosquitofish (Gambusia affinis affinis; hereafter referred to as mosquitofish; Fig. 1a,b)6. We have documented the constraints of sexual dimorphism in copulatory behavior of these fish. We have also described their unique developmental processes. One such process is the postnatal remodeling and anterior shift of the axial and appendicular skeletal elements supporting the male gonopodium, which is a radically modified anal fin. Most recently we have found evidence for gap junction coupling in the remodeling and reprogramming of neural circuits that control the movements of the male gonopodium710.
To paraphrase Viktor Hamburger, the mosquitofish is a teacher of sexual dimorphism11. Its prominent sexual dimorphism in the axial and appendicular skeletal support of the anal fin, a median unpaired fin (Fig. 1c,d), enables structural and functional analysis of sexual dimorphism in vertebrates710,1214.
The mosquitofish is a small, internally fertilizing species of the genus Gambusiini in the family Poeciliidae
(subfamily Poeciliinae, order Cyprinodontiformes). Mosquitofish were initially introduced for mosquito control in areas where mosquito-borne diseases pose a threat to human and animal health and have become almost ubiquitous15,16. These fish comprise a well-studied monophyletic group with high fecundity and...