Sperm and eggs created in dish produce mouse pups
October 5, 2012
These adult mice grew from oocytes, or immature eggs, derived in vitro from induced pluripotent stem cells (credit: Mitinori Saitou and Katsuhiko Hayashi)
After producing normal mouse pups last year using sperm derived from stem cells, a Kyoto University team of researchers has now accomplished the same feat using eggs created the same way, Science Now reports. The study may eventually lead to new ways of helping infertile couples conceive.
The stem cells in both cases are embryonic stem (ES) cells and induced pluripotent stem (iPS) cells. The former are taken from embryos and the latter are adult tissue cells that are reprogrammed to act like stem cells. In theory, both can produce all of the body’s cell types, yet most researchers have been unable to turn them into germ cells, precursors of sperm and eggs.
The Kyoto group, led by stem cell biologist Mitinori Saitou, found a process that works. As with the sperm, the group started with ES and iPS cells and cultured them in a cocktail of proteins to produce primordial germ cell-like cells. To get oocytes, or precursor egg cells, they then mixed the primordial cells with fetal ovarian cells, forming reconstituted ovaries that they then grafted onto natural ovaries in living mice.
Four weeks and 4 days later, the primordial germ cell-like cells had developed into oocytes. The team removed the ovaries, harvested the oocytes, fertilized them in vitro, and implanted the resulting embryos into surrogate mothers. About 3 weeks later, normal mouse pups were born, the researchers report online today in Science.
Further in the future, the technique could lead to a new tool for treating infertility. “This study has provided the critical proof of principle that oocytes can be generated from induced pluripotent stem cells,” Clark says. If applied to humans, it could lead to the ability to create oocytes from iPS cells taken from infertile women.
Comments (7)
by Dr.Pratt
Amazing! The next step is a womb outside of the mamillian carrier. All living things could eventualy grow inside of these carfully contructed biological “ark wombs.”
by Vin
Interesting. This could allow gay couples to have babies using genetic material derived from each parent if I’m not mistaken? Just need a surrogate womb?
by Bri
If I’m not mistaken, in theory men can carry children too. The plecenta graphs itself onto any large enough blood supply. Men’s backs aren’t designed to carry the weight properly and there are other areas that womens bodies are evolved for child rearing. In terms of egg or sperm development, they just need to find the chemical messages that they are using from the surrogates. Could always print a womb with an ink jet printer!
by Vin
lol, I’m sure many women would say their backs aren’t designed to carry the weight properly either. And I think they even dislodge joints during birth. Always fun to speculate, but from what you said it sounds like artificial wombs are conceivable, so to speak and maybe not so far-fetched. I suppose chemical messaging could be synchronised with a single mother linked to any number of artificial wombs.
by Dwight
Tricky thing with that for men would be that the couple would have a 25% chance of having a child with a YY chromosome, which, at least according to a web search which led me to an “Ask a Scientist” page, the lack of an X chromosome would be fatal to the child, pretty well guaranteeing that it not be carried to term. Certainly male birth with an artificial womb would be complicated already, even before adding the YY conundrum. Screening the eggs for the Y chromosome may work, though I’m not a biologist and I’m uncertain of our ability to observe the chromosomes without damaging the egg.
Also, a surrogate mother would likely be more practical.
by Vin
Yah, good point. Y chromosome is always dodgy. Might be best to eliminate the Y chromosome altogether and just have girls: it would probably eliminate crime in one go, lol. But rather than males giving birth, I was thinking of external gestation in an artificial womb furnished with blood supply for placenta and chemical messengers, perhaps linked to an actual pregnant female or computer model of same for synchronisation and feedback. like the old sci-fi trope, the gestation vat. But I appreciate I’m veering off into ‘Brave New World’ territory and remote future.
by Vin
… But if YY embryo’s result, they can always be aborted. I think even with IVF they usually select from a sample of zygotes.