Abnormal development and fetal loss during postimplantation period are concerns 
for production of nuclear transferred animals. Aberrant DNA methylation is one 
of the reasons for poor survival of cloned animals. In mammalian genome DNA, CpG 
islands are preferentially located at the start of transcription of housekeeping 
genes and are associated with tissue-specific genes. The correct and consecutive 
mechanisms of DNA methylation in the CpG islands are necessary for selective 
gene expressions that determine the properties of individual cells, tissues, and 
organs. In this study, we investigated the methylation status of the CpG islands 
of the bovine Leptin and POU5F1 genes in fetal and placental tissues from 
fetuses produced by artificial insemination (AI) and nuclear transfer (NT) at 
days 48 and 59 of pregnancy. Altered DNA methylation was observed in the normal 
and cloned fetal, placental, and endometrial tissues using bisulfite sequencing 
and pyrosequencing. Different tissue-specific methylated regions in the bovine 
Leptin and POU5F1 genes show a variable methylation status in NT fetuses 
compared to AI control.