Influence of the genome region surrounding the estrogen receptor (ESR) gene on litter size in a German Landrace population

This study was designed to analyse the influence of the ESR gene as a QTL f or litter size in a German Landrace population. For the interval mapping an alysis, a total of 709 offspring belonging to 27 paternal half sib families were typed with 10 microsatellite markers surrounding the ESR gene and wit h two newly developed RFLP markers within the ESR gene. The across-family a nalysis did not show evidence for the existence of a QTL affecting the numb er of piglets born alive in first parity in the considered genome region. A lthough the within-family analysis indicated a QTL effect near the ESR gene in one family in both of the analyses the F-ratio did not reach the signif icance threshold. Simulations in order to observe the power Indicate that f amily size needs to be increased further.