(ii) karyoplasts (nuclei with only some residual plasma membrane) are similarly obtained from the blastula stage of the developing embryos of the donor;

(iii) karyoplasts derived from the donor are incubated with enucleated, eggs in the presence of PEG (polyethylene glycol), and fusion is achieved;

(iv) the manipulated egg is transferred to the uterus of a surrogate mother for development.

Techniques have also been developed, where a superior developing embryo may be bisected into two parts using a surgical blade. Each bisected part of the embryo may be separately transferred to an enucleated unfertilized egg.

Such a manipulated egg may then be transferred to the uterus of a surrogate mother for further development.Transfer of whole individual chromosomes or fragments. Chromosomes may be isolated from metaphase cells by hypotonic lysis.

Incubation of these isolated chromosomes with whole cells after coprecipitation with calcium phosphate results, in their incorporation into the nuclei.

The chromosomes once isolated may also be subjected to fractionation using density centrifugation or flow cytophotometry and individual chromosome pairs may be inserted into recipient cells.