For the first time, Chinese biologists bred GM mice from same-sex parents - a pair of females - as well as offspring from a pair of males.
Unlike some other groups of animals, mammals do not have a single species capable of parthenogenesis - reproduction without the participation of the male sex cells. The ability to form such embryos is hampered, in particular, by the "tuning" of the parental DNA: some genes necessary for development operate exclusively in the maternal copy, and some - only in the paternal copy. This adjustment is made due to the chemical attachment of methyl groups to the corresponding sections of DNA, and for the normal development of the offspring it must be "zeroed".
This work was done by Hu Baoyang (Bao-Yang Hu) and his colleagues from the Chinese Academy of Sciences, whose article was published in the journal Cell Stem Cell. The authors isolated a haploid ("single") genome in two female mice, and then used the GM CRISPR technology to spot inclusion of three suppressed genes important for stem cell development. The modified DNA molecules were transplanted into donor eggs, and they were transplanted into female mice that served as surrogate mothers. According to scientists, out of 210 embryos prepared in this way, 14 percent formed normally and led to the appearance of healthy and even reproductive offspring (they are shown in the illustration to the note).
Schematic diagram of the experiment.
Obtaining offspring from two males did not go so smoothly. Scientists had to edit the activity of six genes - out of 1,023 modified embryos, only 1.2 percent made it to birth. However, the mice that were born were twice as large as usual and died soon after birth. Changing the experiment, the scientists identified and "adjusted" seven genes of the DNA of both fathers, but in this case, a pair of mice born lived less than 48 hours.
It should be noted that the work was done to better understand the mechanisms of regulation of embryonic development. In the future, this will not only allow same-sex couples to have children of their own, but will also help correct serious developmental disabilities at an early stage. In addition, technologies for obtaining offspring from parents of the same sex may be indispensable for saving endangered species such as northern white rhinos, the last male of which died about six months ago.
Sergey Vasiliev