The genetic improvement of prolificacy in pigs has increased the disparity of piglets' birth weight within litters Low birth weight piglets are therefore more exposed to the risk of stillbirths, with consequences on animal welfare conditions but also economically for the breeder Interestingly, it is now known that genes subject to genomic imprinting in humans and mice are involved in growth and development processes Genomic imprinting is an epigenetic phenomenon in which genes are mono allelically expressed, depending on a parent of origin PofO methylation, resulting in differentially methylated regions ( between the parental allele Imprinting is important for normal development and growth, and disruptions in imprinting can lead to diseases and disorders This project is therefore based on the hypothesis that imprinting mechanisms could contribute to the explanation of birth weight disparities in piglets As genomic imprinting is still poorly studied in pigs, we propose 1 to characterize the imprinting status of regions that are known to be imprinted in humans and mice 2 to perform linkage/ association studies between the imprinted status and the birthweights phenotypes