Babies Without Men: Creating Sperm From A Woman’s Bone Marrow
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Scientists report today on the ability to create sperm from bone marrow cells.Â Initially performed in men, the technique could potentially be performed in women and lead to a sperm cell made from a woman’s body.Â You got it right- that cell could then fertilize an egg leading to the first female-female conception in human history.
AsÂ a fertility specialist I couldn’t resist this story and wanted to share the reality and the hype.Â Prof. Karim Nayernia, Professor of Stem Cell Biology at the Instatute of Human Genetics at the Univeristy of Mewcastle on Tyne led the project reported in Biology of Reproduction.Â A summary of the study was released in the Independent today.
The researchers said they had already produced early sperm cells from bone-marrow tissue taken from men. They believe the findings show that it may be possible to restore fertility to men who cannot naturally produce their own sperm.
But the results also raise the prospect of being able to take bone-marrow tissue from women and coaxing the stem cells within the female tissue to develop into sperm cells, said Professor Karim Nayernia of the University of Newcastle upon Tyne.
The report suggests that “Scientists are seeking ethical permission to produce synthetic sperm cells from a woman’s bone marrow tissue after showing that it possible to produce rudimentary sperm cells from male bone-marrow tissue.”
The Two Mommy- No Daddy Baby Making Research Plan:
“Theoretically is it possible,” Professor Nayernia said. “The problem is whether the sperm cells are functional or not. I don’t think there is an ethical barrier, so long as it’s safe. We are in the process of applying for ethical approval. We are preparing now to apply to use the existing bone marrow stem cell bank here in Newcastle. We need permission from the patient who supplied the bone marrow, the ethics committee and the hospital itself.”
If sperm cells can be developed from female bone-marrow tissue they will be matured in the laboratory and tested for their ability to penetrate the outer “shell” of a hamster’s egg – a standard fertility test for sperm.
“We want to test the functionality of any male and female sperm that is made by this way,” Professor Nayernia said. But he said there was no intention at this stage to produce female sperm that would be used to fertilise a human egg, a move that would require the approval of the Human Fertilisation and Embryology Authority.
This same group reported last year that they created artifical sperm from embryonic sperm cells in mice.Â
(They) isolated stem cells from blastocysts, which are early-stage embryos only a few days old.Â From these cells were extracted those that would go on to form sperm, known as spermatogonial stem cells (SSCs). The SSCs were then cultured in the laboratory, and when some developed into sperm, they were injected into female mouse eggs and grown into early-stage embryos. The embryos were transplanted into the wombs of surrogate mothers.
The Genetic Disaster That Could Result: Faulty Imprinting.Â There is a huge genetic time-bomb here.Â The genetic phenomenon called imprinting.Â This describes the situation where a particular gene is marked or imprinted with a tag that says if it came from the mother or father- and more importantly only one of the other is active.Â For example for a particular gene it’s possible that only the maternal copy gene could be active and the copy that comes from the mother could be switched off.Â If this process goes wrong (mom and dad copy mistakes) then severe genetic diseases can result.Â
However, it is now known that the expression of a small number of the 30,000 or so genes in the cells depends on whether the gene copy was passed down from the father or the mother. This process, whereby the expression of a gene copy is altered depending upon whether it was passed to the baby through the egg or the sperm, is called imprinting.The term “imprinting” refers to the fact that some chromosomes, segments of chromosomes, or some genes, are stamped with a “memory” of the parent from whom it came: in the cells of a child it is possible to tell which chromosome copy came from the mother (maternal chromosome) and which copy was inherited from the father (paternal chromosome). This expression of the gene is called a “parent of origin effect” .