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Scientists have created healthy offspring from genetically infertile male mice, providing a new method of correcting a genetic cause of human infertility.
Human sex is determined by the X and Y chromosomes. Usually, girls have two X chromosomes XX and boys have one X and one Y XY, but 1 in 500 boys are born with an extra X or Y.
Having three rather than two sex chromosomes can hinder formation of mature sperm and cause infertility.
Researchers have discovered a way to remove the extra sex chromosome to produce fertile offspring.
If the findings can be safely transferred into humans, it might eventually be possible for men with Klinefelter syndrome XXY or double Y syndrome XYY that are infertile to have children through assisted reproduction using this method.
Researchers took small pieces of ear tissue from XXY and XYY mice, cultured them, and collected connective tissue cells known as fibroblasts. They turned the fibroblasts into stem cells and noticed that in the process, some of the cells lost the extra sex chromosome.
With an existing method, they used specific chemical signals to control the stem cells into becoming cells that have the potential to become sperm. These cells developed into mature sperm when injected into the testes of a host mouse.
The researchers then harvested these mature sperm and used them through assisted reproduction to create healthy, fertile offspring.
Sperm cells have been created in the laboratory, offering hope for a cure for a common cause of male infertility.
About 1 in 500 men have an extra X or Y chromosome, which prevents their sperm production.
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