Scientists Turn Human Skin into Fertilizable Eggs in Fertility Breakthrough

Scientists in the United States have, for the first time, made early-stage human embryos by manipulating DNA taken from people's skin cells and then fertilising them with sperm. The step is said to be a major one in the quest to develop lab-grown eggs or sperm to one day help people conceive and overcome infertility. However, according to the Oregon Health and Science University team, which conducted the experiment, it resulted in abnormalities in the chromosomes, and so it may take another decade of additional research before such a technique might be ready for trials in people. Scientists say the technique could overcome infertility due to old age or disease by using almost any cell in the body as the starting point for life. It could even

allow same-sex couples to have a genetically related child.

How was the experiment conducted?

For the study, published in the journal Nature Communications, the team removed the nucleus from a human egg cell and replaced it with the nucleus from a human skin cell. But a skin cell contains two sets of chromosomes, and eggs and sperm are supposed to each contain only one set that combine during fertilization. And then egg-like cells were induced to discard extra chromosomes, injected with donated sperm, and jump-started post-fertilization development. Around 9 per cent lived for six days in lab dishes, reaching the blastocyst stage of early embryo development, before the experiment was halted, because all the chromosomes were abnormal in several ways. “We kind of developed this new cell division that can reduce chromosome number,” said study senior author Shoukhrat Mitalipov, OHSU’s embryonic cell and gene therapy director. “It’s still not good enough to make embryos or eggs genetically normal.” He called the initial findings proof-of-concept and said his team is working on improvements. Scientists have hailed the results, yet are troubled by the abnormalities. A few believe that, despite failure at the final level, it is an important step.

Women can be potential beneficiaries

According to the scientists, while women are expected to be the primary beneficiaries, skin cells used to make the eggs need not come from potential mothers. “We used female skin cells in this study, but you could use skin cells from males as well,” Mitalipov told the Guardian. “You could make eggs for men, and that way, of course, this would be applicable to same-sex couples.” In another breakthrough experiment conducted in the 90s in Scotland, a team of scientists had used similar somatic cell nuclear transfer to create Dolly the sheep. The process had involved plucking the nucleus from an adult sheep cell and placing it into a sheep egg that had its own nucleus removed. The resulting egg was carried to term in Dolly’s surrogate mother. Similarly, the Oregon team collected skin cells from women and removed the nucleus from each. The nucleus contains the 46 chromosomes that carry the 20,000 or so genes that comprise the human genetic code. Each skin cell nucleus was placed in a healthy donor egg that had its own nucleus removed. The major challenge the scientists faced was that healthy human eggs contain only 23 chromosomes. A further 23 arrive in the sperm on fertilisation and are needed for the fertilised egg to develop into an embryo and ultimately a baby.