Australian researchers have devised a method of fertilising eggs without sperm. Dr Orly Lacham-Kaplan's research unit at the Monash University's Institute of Reproduction and Development in Melbourne developed the procedure with the hopes that it could one day serve as a viable alternative to sperm donation for infertile men.
Theoretically, it may also be used to produce biological children for homosexual partners of either sex. The technique relies on somatic cell transfer and is a modification of current cloning technology.
Somatic nuclear cell transfer, the process of transferring a cell from any part of the body into an oocyte nucleus, was used in cloning Dolly the sheep. Oocytes and sperm are haploid, with one set of chromosomes, whereas somatic cells are diploid, with two chromosomal sets. Dolly was created by transferring a full set of chromosomes from an adult somatic cell into an oocyte that had been stripped of its own genetic material.
By contrast, in the method used by the researchers at Monash, the oocyte retains its chromosomes but the somatic cell is persuaded, via chemical means, to jettison one set of its own after fertilisation. The resulting fertilised egg ends up with two sets of chromosomes, one set from the mother and the second from the adult cell. The resultant “fertilised” egg is prompted to divide through electric shock stimulation.
So far, the group has fertilised oocytes from mice with an adult cell from a female mouse and allowed the resultant embryos to develop in culture to the blastocyst stage. A mouse needs 21 days of gestation for full development. In culture these mouse embryos have grown to day 5 without an outward sign of abnormality.
The researchers plan to implant the embryos into surrogate mouse mothers for further development. They have yet to determine whether genetically normal mouse pups with full reproductive capability would result. It should take at least a year to determine if normal mice will develop.
Although the work is in its preliminary stages, it represents an advance in the field of reproductive genetics. For infertile couples or same sex couples who want children with a genetic contribution from each partner, it provides hope.
Figure.
Dr Lacham-Kaplan”s work in Melbourne could help infertile men