Physical mapping of porcine seasonality genes

Seasonal infertility in sows is a problem in the pig industry characterized by delayed onset of puberty in summer and decreased farrowing rate resulti ng from silent oestrus and aborted pregnancy. Summer infertility is thought to be influenced by heat, sunburn and stress. However, the strongest contr ibutory factor is photoperiod. The difference in seasonality between wild b oar and commercial pig breeds suggests that there may be a genetic componen t to this trait. The maps and associated molecular tools emerging from the pig genome project have created opportunities to examine the genetic compon ent of seasonal infertility. We are identifying and mapping genes that are likely to be involved in biological clock mechanisms and the melatonin path ways as candidate seasonality genes.