RELEVANCE OF INTERSEXUALITY TO BREEDING AND REPRODUCTIVE BIOTECHNOLOGY PROGRAMS - XX SEX REVERSAL IN PIGS

In pigs, the frequency of intersexuality ranges from 0.1 to 0.6%. Econ omic losses are significant and result from sterility, urogenital infe ctions and downgrading of carcasses because of boar taint. To elucidat e the genetic aetiology of pig sex reversion, 50 intersexes from a clo sed breeding herd were analysed. The majority have a 38,XX karyotype w ithout Y chromosome sequences. Phenotypically, the animals range from true hermaphrodites to XX males with or without genital ambiguities. A nalysis of crosses between parents of intersexes showed that the trait is inherited and caused by the same mutation in the Large White breed . Investigations are currently being carried out to isolate a genetic marker linked to intersexuality using genetic map of the porcine genom e. Such a marker will be useful in eradicating the mutation in pig bre eding herds and in permiting the isolation of the gene responsible. (C ) 1996 by Elsevier Science Inc.