Parthenogenic Reproduction in Mammals by Genetic Modification


This female mouse, shown at an age of 4.5 months with her offspring, has no father. The mouse grew from a single unfertilised egg extracted from a female mouse (can one say “mother” in this age and circumstance?), then subjected to targeted DNA methylation rewriting by messenger RNA designed to modify seven imprinting control regions in the genome which are usually activated by the process of fusion with the DNA from sperm from a father. This allowed the unfertilised egg to develop into viable offspring, of which the mouse above is an example. That mouse was subsequently bred with a male mouse the old-fashioned way, resulting in the pups shown, which were found to exhibit no genetic abnormalities due to the genetic modification of the mother.

This work is described in a paper, “Viable offspring derived from single unfertilized mammalian oocytes”, published in the 2022-03-07 issue of PNAS. Full text is available at the link.


In mammals, parthenogenesis is limited because of problems arising from genomic imprinting. Here, we report live mammalian offspring derived from single unfertilized eggs. This was achieved by the targeted DNA methylation rewriting of seven imprinting control regions. By designing guide RNAs with protospacer adjacent motif (PAM) sequences matching one allele but not the other, dCas9-Dnmt3a or dCpf1-Tet1 enables targeted DNA methylation editing in an allele-specific manner. The success of parthenogenesis in mammals opens many opportunities in agriculture, research, and medicine.


In mammals, a new life starts with the fusion of an oocyte and a sperm cell. Parthenogenesis, a way of generating offspring solely from female gametes, is limited because of problems arising from genomic imprinting. Here, we report live mammalian offspring derived from single unfertilized oocytes, which was achieved by targeted DNA methylation rewriting of seven imprinting control regions. Oocyte coinjection of catalytically inactive Cas9 (dCas9)-Dnmt3a or dCpf1-Tet1 messenger RNA (mRNA) with single-guide RNAs (sgRNAs) targeting specific regions induced de novo methylation or demethylation, respectively, of the targeted region. Following parthenogenetic activation, these edited regions showed maintenance of methylation as naturally established regions during early preimplantation development. The transfer of modified parthenogenetic embryos into foster mothers resulted in significantly extended development and finally in the generation of viable full-term offspring. These data demonstrate that parthenogenesis can be achieved by targeted epigenetic rewriting of multiple critical imprinting control regions.

In 2010, feminist Hanna Rosin published a book, based upon an earlier cover story in The Atlantic, titled The End of Men, in which she argued that women had “pulled decisively ahead [of men] by almost every measure”, thus decisively winning the “gender war”. In 2014, she wrote an opinion piece in Time titled, “Men Are Obsolete” (emphasis mine):

Are men literally obsolete? Of course not, and if we had to prove that we could never win. For one thing, we haven’t figured out a way to harvest sperm without them being, you know, alive. But in order to win this debate we have to prove that men, quote unquote, as we’ve historically come to define them — entitled to power, destined for leadership, arrogant, confused by anything that isn’t them. As in: “I don’t understand. Is it a guy dressed up like a girl? Or a girl dressed up like a guy?” They are obsolete.

Patience, Hanna…they’re working on it.


Here we have the “intellectual” underpinnings of the next round of eugenics. These are the same people who would applaud (or participate in) mass killings of men. Naturally, their “principles” are portable. They can be instantly re-deployed during any 2 minute hate against the despised “identity group” (voluntary or otherwise) du jour.


Reminds me of the 1984 comedy “Sexmission” by Juliusz Machulski. Short summary: parthenogenic reproduction in mammals is not sustainable :wink:


I don’t give a …ph…que what anybody sez. I would never be turned on enough by another female to reproduce with her. Nor would I feel that I, alone, should populate the next generation. Pleeeze, go ‘way now.


In parthenogenesis, only one female is involved. There is no recombination involved in producing the genome of the offspring: all offspring are clones of the mother. Parthenogenesis occurs in nature among some algæ, plants, and invertebrates and in a few vertebrate species (amphibians, fish, reptiles, and birds). Some species (for example, the Komodo dragon) can reproduce either sexually or through parthenogenesis, while others are completely asexual and only reproduce via parthenogenesis. There are more than 80 known species of lizards that reproduce only by parthenogenesis. These are believed to have evolved from sexually reproducing species who lost the ability to reproduce sexually for a variety of reasons such as inbreeding and mutation. Because these species have lost the gene-shuffling which causes variation among the population, they are believed to be more vulnerable to environmental changes to which the more diverse population produced by sexual recombination can adapt.

Parthenogenesis has never been observed among mammals in nature. Parthenogenesis has been induced experimentally in mice and monkeys, but previous experiments have usually resulted in abnormalities in development of the offspring due to presence of maternal genes in regions of the genome where paternal genes are expected. The present experiment uses genetic modification to disable the activation of these excess maternal genes, leading to the reported normal development of offspring. Because there is no source of a Y chromosome, all offspring produced this way are female.


No, I know, you’re right.