Meeting Abstract

P2.69  Thursday, Jan. 5  A FORWARD GENETIC SCREEN FOR ZYGOTIC AND STERILE MUTANTS IN THE MANGROVE KILLIFISH (KRYPTOLEBIAS MARMORATUS ) SUCAR, S.*; MOORE, G.; ARD, M.; NEWSOME, J.M; BERNHARDT, L.; RING, B.C; Valdosta State University; Valdosta State University; Valdosta State University; Valdosta State University; Valdosta State University; Valdosta State University

The mangrove killifish is unique among vertebrates due to its self-fertilizing mode of reproduction analogous to the invertebrate nematode model system, Caenorhabditis elegans . This fish develops externally, is easy to maintain, reaches sexual maturity in about 100 days, making it a desirable, but underutilized developmental genetic model organism. The genetic factors that control the formation of the ovotestis in this species are unknown. We performed a 3 generation genetic screen in order to identify mutants that disrupt normal ovotestis development. The P generation was exposed to different concentration of N-ethyl-N-nitrosourea and 284 F1 fish were screened. 73 F1 fish displayed zygotic defects in their F2 offspring (25%). In order to confirm the zygotic mutant phenotypes into the next generation, 8-10 F2 fish are reared to maturity to form a F1 family. The progeny of each F2 fish are screened to confirm zygotic phenotypes into the next generation. Thus far, we have screened 24 F1 families (33%). Of those screened, 53% of the F2 fish confirmed the zygotic phenotypes as expected in proper Mendelian ratios. In a simultaneous screen of these F1 families, we are able to identify adult F2 fish that are sterile. Sterile fish fall into three phenotypic classes: non-egg layers and non-viable embryos (maternal effect) and non-fertilized embryos (paternal effect). Thus far, we have identified 7 sterile families (29%). We are currently screening another 125 F2 to further confirm zygotic mutations and to identify more sterile families. This screen provides proof of principle that the mangrove killifish is a powerful model for developmental genetics.