Nuclear reprogramming and molecular characterization of pigs derived from somatic cell nuclear transfer

Date of Completion

January 2006


Biology, Molecular




This thesis investigated the extent of nuclear reprogramming and normalcy of cloned pigs in terms of their telomere lengths and gene expression. We established the telomere length profile in major porcine organs of different ages and showed that, although they were derived from donor cells that have shortened telomere, cloned pigs have normal telomere lengths compared to their age matched controls. Abnormal expression levels of selected X-linked and imprinted genes were observed in both newborn deceased and one month old surviving cloned pigs. Tissue specificity of gene expression was correctly restored for all genes studied. No correlation was found between the expression of imprinted gene and the low-body-weight phenotype of cloned pigs in either age group. The extent of aberrant expression of X-linked genes reduced in the surviving clones, suggesting a correlation between the viability of clones and the normality of their gene expression. Global profiling of gene expression in bovine in vitro-produced fetuses showed no difference with the in vivo-produced fetuses in both liver and placenta tissue, suggesting that the abnormalities in cloned animals stems from factors other than oocyte in vitro maturation and embryo culture. ^