Eshel, O., Hebrew University of Jerusalem, Robert H. Smith Faculty of Agriculture, Food and Environment, P.O. Box 12, Rehovot, 76100, Israel, Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Shirak, A., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Weller, J.I., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Slossman, T., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Hulata, G., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Cnaani, A., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Ron, M., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Shirak, A., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Weller, J.I., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Slossman, T., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Hulata, G., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Cnaani, A., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Ron, M., Department of Cattle and Genetics, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan, 50250, Israel
Genetic markers in tilapia species associated with loci affecting sex determination (SD), sex-specific mortality or both were mapped to linkage groups (LG) 1, 2, 3, 6 and 23. The objective of this study was to use these markers to fine-map the locus with the greatest effect on SD in Oreochromis niloticus. Our parental stock, full-sibs of Nile tilapia (Swansea origin), were divided into three groups: (i) untreated, (ii) feminized by diethylstilbestrol and (iii) masculinized by 17α-methyltestosterone. We analysed the first group for association of microsatellite markers representing these five LGs. The strongest association with gender was found on LG23 for marker UNH898 (χ2; P = 8.6 × 10-5). Allele 276 was found almost exclusively in males, and we hypothesized that this allele is a male-associated allele (MAA). Sex-reversed individuals were used for mating experiments with and without the segregating MAA. Mating of individuals lacking the MAA resulted in all-female progeny. Mating of two heterozygotes for MAA gave rise to 81 males and 30 females. Analysis of association between gender and genotypes identified the MAA in 98.6% of males as opposed to 8.0% of females (χ2; P = 2.5 × 10-18). Eight markers that flank UNH898 were genotyped to map the locus on LG23 within a confidence interval of 16-21 cM. Mating of homozygous individuals for MAA is underway for production of all-male populations. © 2010 The Authors, Animal Genetics © 2010 Stichting International Foundation for Animal Genetics.
