Meeting Abstract

S2-1.7  Wednesday, Jan. 4  Establishing Developmental Genetics in the Mangrove Killifish (Kryptolebias marmoratus) SUCAR, S.; NEWSOME, J.M.; MOORE, G.L.; RING, B.C.*; Valdosta State University; Valdosta State University; Valdosta State University; Valdosta State University bcring@valdosta.edu

The mangrove killifish is a synchronous hermaphroditic fish, which utilizes an ovotestis for reproduction resulting in isogenic lineages analogous to the invertebrate nematode model system, Caenorhabditis elegans. This fish develops externally, is easy to maintain and reaches sexual maturity in about 100 days making it a desirable but underutilized developmental genetic model organism. Here we present an ongoing forward genetic screen with the commonly used chemical mutagen, N-ethyl-N-nitrosourea (ENU). Parental isogenic lines Hon9, Hon11, and 50.91 were chosen for mutagenesis based on their genotype, fecundity, viability, average developmental stage of oviposition, and ease of husbandry. ENU treated parents were self-crossed (P; N=34) followed by observation of their offspring across three generations. Mortality, egg production, and fertility of the P fish were recorded over a 10 week period and compared to untreated controls and pre-treatment values. 61% of 7,350 F1 embryos collected were viable of which 1,334 were hatched and raised to maturity (18%) and 284 (genomes) were self-crossed and their F2 offspring screened for zygotic defects during early development. 73 F1 fish produced mutant phenotypes belonging to six different phenotypic classes. We are currently confirming these zygotic mutants into the F3 generation and simultaneously identifying sterile mutant adults. The types and frequencies of mutants in our ongoing genetic screen are documented and compared to other fish models. Taken together, the mangrove killifish represents a powerful and economical model organism which will complement future developmental genetic screens in vertebrates.