Same-sex breeding of healthy mammals has succeeded, according to a study published on Thursday highlighting how scientists genetically reproduced baby lab mice from two females, CNN reported.
The key lay in a combination of stem cells and targeted gene editing, researchers at the Chinese Academy of Sciences revealed in their report published in the journal Cell Stem Cell.
Scientists have previously been able to produce mice with two mothers by deleting certain imprinted genes from immature eggs, but the mice were born with defects and abnormalities.
Using that as the basis of their study, the international research team set about expanding upon the concept by including the use of haploid embryonic stem cells (ESCs), which contain half the normal number of chromosomes and DNA from only one parent.
They then combined this with targeted gene editing, which was injected into eggs from another female mouse, which produced 29 healthy, normal mice from 210 embryos, which lived to adulthood and had babies of their own.
“We were interested in the question of why mammals can only undergo sexual reproduction,” said co-senior author Qi Zhou, according to Eureka Alert. “We have made several findings in the past by combining reproduction and regeneration, so we tried to find out whether more normal mice with two female parents, or even mice with two male parents, could be produced using haploid embryonic stem cells with gene deletions.”
A similar approach was undertaken with two male mice and, while they produced 12 live, full-term babies, the pups survived only 48 hours after birth.
This is not the first time that scientists were able to achieve such results.
In 2011 they used a different method that focused on a female intermediary produced from the first father's stem cells to mate with the second father.
However, ethical and practical obstacles entailed posed an issue for this technology.
Co-senior author Wei Li noted that their findings showed what was possible to achieve.
“We saw that the defects in bimaternal mice can be eliminated and that bipaternal reproduction barriers in mammals can also be crossed through imprinting modification,” he said. “We also revealed some of the most important imprinted regions that hinder the development of mice with same sex parents, which are also interesting for studying genomic imprinting and animal cloning.”
However, other researchers felt the method through which this was achieved is impractical with current technology.
“The tremendous amount of genetic modification needed in order to do what they (Chinese researchers) did, makes it implausible to use it in anything other than research,” said Dr. Tim Hore, an expert in epigenetics and development at the University of Otago, according to CNN.
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