Arti­fi­cial Sperm!

HempDon’t pay atten­tion for and few days and see what happens!

From: sci​enceal​ert​.com

Sci­en­tists have made the best arti­fi­cial sperm yet, and they’re breed­ing mice with it.

Sci­en­tists have used embry­onic stem cells to grow the most effec­tive ‘test-​tube’ sperm cells ever, demon­strat­ing how they can be used to fer­tilise mouse eggs, and pro­duce healthy, fer­tile offspring.

The cells are the first in the world to meet a set of cri­te­ria known as the ‘gold stan­dard’ for arti­fi­cial sperm, set by three fer­til­ity researchers in 2014. “The achieve­ments of this paper are very remark­able,” John Schi­menti of Cor­nell Uni­ver­sity, one of the researchers who defined the gold stan­dard, told New Sci­en­tist. “I’m not aware of another group hav­ing pro­gressed this far.”

The team from Nan­jing Med­ical Uni­ver­sity in China haven’t used stem cells to cre­ate actual, proper sperm cells, but they have man­aged to cre­ate arti­fi­cial sper­matids, which are imma­ture ver­sions of sperm that have not yet grown tails. With­out tails, these sper­matids can’t swim, so they’re injected into a mouse egg via IVF instead.

To reach the gold stan­dard for arti­fi­cial sperm, the researchers had to demon­strate that at var­i­ous stages of growth, the cells were retain­ing a num­ber of cru­cial char­ac­ter­is­tics, such as the right num­ber of chro­mo­somes and the right per­cent­age of donor DNA. And that’s no easy feat, as every other attempt to ade­quately con­trol all the key stages of sex cell divi­sion has failed.

Until now, researchers have strug­gled to prove that they have pushed cells through an impor­tant but com­pli­cated divid­ing process that leaves cells with only half of the father’s chro­mo­somes,” Andy Cogh­lan reports for New Sci­en­tist.

So not only has the team appeared to mas­ter the cell divi­sion process, they were also able to pro­duce healthy off­spring — two fac­tors that helped them meet the elu­sive gold standard.

We think our work is the first to mon­i­tor and exam­ine all require­ments for suc­cess­ful meio­sis,” said one of the team, Jia­hao Sha.

So how did they do it? The researchers took embry­onic stem cells from male mice and exposed them to chem­i­cals called cytokines that trig­gered their trans­for­ma­tion into germ cells — a type of cell that gives rise to sex cells (eggs or sperm). While the cells were dif­fer­en­ti­at­ing, they were placed next to testes-​like tis­sue and exposed to the male sex hor­mone, testos­terone, to coax them into a sper­matid form.

The tech­nique has so far only been tested on mice, so we have no idea if it’ll work on humans deal­ing with fer­til­ity prob­lems. But the hope is that one day, sci­en­tists could extract cells from an infer­tile man — such as skin or cheek cells — revert them to an embry­onic stem cell-​like state, and then con­vert those into arti­fi­cial sper­matids for use in IVF.

And this isn’t such a crazy propo­si­tion, as Akshat Rathi reports over at Quartz: “Past research has shown that skin cells can be con­verted into pluripo­tent stem cells, which are equiv­a­lent to embry­onic stem cells. These pluripo­tent stem cells have even been con­verted into pre­cur­sors of sperm and egg cells.”

While this could work in the­ory, the eth­i­cal ques­tions of doing so means we’re a very long way off actu­ally using the tech­nique to cre­ate humans.

How can we tell if sper­matids made in a lab­o­ra­tory are really of the same high qual­ity as those made and tested by nat­ural selec­tion in the testis?” biol­o­gist Peter Dono­van from the Uni­ver­sity of Cal­i­for­nia, Irvine, who was not involved in the study, pointed out to The Verge.

Just as allow­ing babies to be born from genet­i­cally mod­i­fied embryos brings up some seri­ous con­cerns about ‘designer babies’ bypass­ing the nat­ural order of things, if arti­fi­cial sperm were used to cre­ate humans, we would have to rec­on­cile the prob­lem of whether or not they are inher­ently dis­ad­van­taged in some way, and that’s no easy ques­tion to answer.

But with researchers in France and Japan fol­low­ing close on the heels of Sha and his team in the race towards arti­fi­cial human sperm, we’re going to have to fig­ure it out sooner rather than later.

The results have been pub­lished in Cell Stem Cell.

Webmaster’s note: To me this is very much like a clone, as you would be only get­ting the mother’s genetic markers.

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