Production of four identical calves by the separation of blastomeres from an in vitro derived four-cell embryo

Abstract

The blastomeres of two in vitro derived four-cell embryos were separated and transferred individually into surrogate zonae pellucidae, then co-cultured with bovine oviductal epithelial cells for five days until blastulation. Pairs of the quarter blastocysts were co-transferred with trophoblastic vesicles into each of four synchronised Holstein heifers, three of which were diagnosed pregnant at 28 days gestation, carrying twin fetuses. Four genetically identical bull calves were delivered by elective caesarean section at term pregnancy. One pregnancy was terminated at 56 days.

Development of single mouse blastomeres into blastocysts, outgrowths and the establishment of embryonic stem cells

“…This study also supported the notion that sister BTMs may be capable of compensating the lost or damaged BTMs of an embryo. Nonetheless, a very limited number of successful cases of producing a full set of identical offspring by either embryo splitting or nuclear transplantation were reported (Johnson et al 1995, Kwon & Kono 1996. Our results support the idea that not all of the BTM-derived embryos and outgrowths expressed ICM marker.…”

“…the separation of a two-cell embryo has been reported by several groups (Willadsen 1979, Willadsen & Polge 1981, Ozil 1983, Allen & Pashen 1984, Tsunoda et al 1985, Papaioannou et al 1989, there was only one report on the production of a complete set of quadruplet calves (Johnson et al 1995). In most cases, live offspring have not resulted from a full set of bisected embryos (Tarkowski 1959, Tsunoda & McLaren 1983, Chan et al 2000.…”

“…On the contrary, two-, four-, and eight-cell sheep embryos show no difference in producing monozygotic twins (Willadsen 1979). Although monozygotic twins have been produced by separating two-cell embryos in some species (Willadsen 1979, Willadsen & Polge 1981, Ozil 1983, Allen & Pashen 1984, Tsunoda et al 1985, Matsumoto et al 1989, there was only one report showing the pluripotency of fourcell BTMs that produced quadruplets (four identical calves) (Johnson et al 1995).…”

Cloning in cattle: from embryo splitting to somatic nuclear transfer

“…Another approach using blastomere separation and culture of isolated blastomeres exceptionally produced one set of triplets from 8 cell stage embryos [55]. One set of quadruplets was reported in Canada after culture and transfer of blastomeres from a four cell stage embryo [21] [16,56]. Then the more advanced morula stage embryos, used as donor embryos, result in a higher mean number of cloned blastocysts per parent embryo.…”

Totipotency: What It Is and What It Is Not

“…In most mammals, only the first two cells of the embryo remain totipotent, that is, able to generate a complete embryo on their own when separated [145][146][147], perhaps in part because cells no longer have sufficient mass to continue development [148,149]. In rare cases, totipotency is preserved until the four-cell stage [150], with there being one reported case of a child born after transfer of a four-cell embryo in which only one of the blastomeres was judged to be alive [151]. There has also been one report in pigs of totipotency persisting until the eight-cell stage [152].…”