Scientists from Cornell University in New York, USA are speculating that cloning the human male genome could help men with low sperm counts.
In men with few sperm it can be challenging to select the sperm for use in IVF. Normally a single sperm will be injected directly into the egg, but this procedure has a high failure rate.
The idea is, to genetically clone the sperm so that exact replicas can be produced, enabling the man to have an average chance at conception.
Professor Tachuchi, from the university, said
'If we were able to propagate it, while maintaining its normal chromosomal make-up, its ability to fertilise and to participate in full-term embryo development, we would be able to enhance the number of chances of conception of many couples, and hence improve the chances of an on-going pregnancy."
The cloning of sperm cells has been practiced on mice by injecting a mouse sperm into a mouse egg which had had its nucleus removed. In this way, it cloned the male genome. On studying the clones, 80% were found to be identical. They created 64 blastocysts (embryos in a very early stage of development) and implanted them into 6 host mother mice. Of these, only 4 developed into normal baby mice.
Unfortunately, there was a fairly high level of genetic abnormality shown in some of the cloned mice, which is what scientists expected. The team are looking at ways to address this problem. They think that by trying to produce more than one embryo per sperm sample, they will have a higher chance of creating healthy embryos.
"We believe that replication of the male genome, in addition to providing hope for infertile couples, could also provide the opportunity to use replicates of the sperm nucleus for diagnostic purposes'"added Professor Tachuchi, '"If you only have one healthy sperm you would be reluctant to use it for anything but fertilisation. But with this technique it should be possible to create enough to be sure that the embryo which is implanted is healthy."
So if it works it could have the extra benefit of securing a stronger embryo, which of course makes a healthier baby, as well as assisting infertile men in becoming fathers.
Using cloning of male genes to treat infertility, however, is still very much in the infancy stages of research and it will be years, if at all, before scientists know how to successfully clone sperm without causing gross abnormalities in the resulting fetus.
Source: European Society for Human Reproduction and Embryology. July 2007.
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