Patent ID: 7659443

Claim:
A method for constructing a nucleus-implanted egg of a mouse, the nucleus-implanted egg having a haploid genome set derived from ng ovum and a haploid genome set from fg ovum, which comprises the steps of (1) introducing a mouse primitive ovarian follicle egg (ng ovum) into a mouse nucleus-deleted egg in a germinal vesicle stage (GV stage egg) and then developing the obtained egg to MII phase (second meiosis metaphase) by in vitro maturing and culturing to prepare a first nucleus-implanted egg, and (2) extracting all of MII phase chromosome from said first nucleus-implanted egg and introducing said MII phase chromosomes into a second mouse MII phase egg (fg ovum) to prepare a second nucleus-implanted egg, wherein ovum from which the 13 kb totaled H19 genes and upstream regions thereof that undergoes epigenetic modification during the generation of sperm is deleted is used as the ng ovum or fg ovum.