XX. Generation
Scientists call asexual reproduction parthenogenesis – this is a Greek word that literally means “virgin creation” (from the Greek: parthenos – virgin, genesis – creation). Parthenogenesis occurs in a wide variety of organisms, including plants, insects, fish, reptiles, and even birds.
Until recently, scientifically confirmed cases of parthenogenesis in mammals, including humans, were not documented. Despite
hypothetically, women are quite capable of starting to reproduce their own kind without the participation of men, since they have everything in their bodies for this.
Females have two sex X chromosomes, one from the father and one from the mother. Males inherit the X from their mothers and fathers, a small Y extension with almost no genes in it. But the main issue is that males do not have reproductive structures to bear children.
With the development of genetic technologies, including genome editing, scientists began to develop artificial methods of parthenogenesis. In 2022, Shanghai scientists achieved success by publishing in the authoritative scientific journal PNAS. results experiments with mice. Female mice managed not only to get pregnant perfectly, but also to give birth to full-fledged offspring. Several females who “conceived” using artificial parthenogenesis were also successful mothers, which convinced the scientific community that asexual reproduction was possible in mammals.
“The participation of the sperm cell in mammalian reproduction is not necessary simply because it carries the missing half of the genome. A professor, one of the leading researchers at the Institute of General Genetics, told socialbites.ca that the embryo carries factors that initiate its normal development. NI Vavilov RAS, Professor of the Department of Genomics and Bioinformatics and Head of the Scientific and Educational Center for Genomics Research of the Siberian Federal University Konstantin Krutovsky. – Not only should genes come with sperm, some have to be in a special state. These initiating factors are necessary to initiate cell division and development, turning it into an embryo.
What did Shanghai scientists do? They edited the “female” genes and gave them the desired state in immature eggs (oocytes) whose haploid (half) maternal genome completes into a diploid (full) set of chromosomes by injecting the other half of the maternal genome – this is how Fertilization is simulated. The other half of the genome is taken from the so-called polar body, which is formed during meiosis (dividing the chromosome number of the nucleus of a eukaryotic cell in half) during the formation of mouse eggs. This is what made it possible to initiate the process of transforming a cell into an embryo.
The main conclusion that can be drawn from this successful experiment is that a phenomenon such as parthenogenesis can be controlled.
If it can be controlled in mice, the next step is to try the technology in monkeys. Then try it on human cells in countries that are allowed to work with human stem cells in the earliest stages of embryo development.
“But if it worked in rats, it will work 100% in humans,” Krutovsky believes. “Another thing is that this technique will need to be worked on.”
Like two drops?
It is clear that with the help of artificial parthenogenesis technologies, women can only give birth to girls. And these – to give birth and give birth to new girls, perpetuating the female sex.
Will the daughter born to a mother using the “perfect pregnancy” method presented in the study of Shanghai scientists definitely look like her?
Answer is no. For this, half of the genome is taken from an oocyte (immature egg) and the other half from the polar body of another oocyte. In a cell thus formed with a complete set of chromosomes, there will already be a slightly different combination of genes, but the resemblance to the mother will be enormous.
“Instead of using a polar body, possibly the nuclear genomes of two eggs could be merged or one of them injected into the nucleus of another egg,” Krutovsky said. Said. – But even then, an exact copy of the mother won’t work because the genes are reassembled in the process of meiosis. Different eggs carry different gene sets (different forms). Alleles inherited from parents are different. A daughter born from the union of two eggs will resemble both her mother and her relatives.
However, there is another mechanism by which the birth of a daughter from the mother is possible without the participation of the father.
“By disrupting meiosis during egg formation (which occurs during intrauterine development in the female fetus, as in mammals), it is possible to induce the formation of non-reduced eggs with a full set of chromosomes and then initiate ovulation. Professor Krutovsky said that with further epigenetic reprogramming of the egg and the initiation of fetal development, she is a mature girl. – In this case, the developing child will be an exact copy of the mother. But I have not seen such studies in the scientific literature.
What did the tumors say?
The fact that eggs with a full set of chromosomes can exist in a woman’s body became known after scientists found the composition of mature teratomas – ovarian tumors.
As it turned out, they develop from non-reduced eggs that carry a complete or partially complete set of maternal chromosomes due to a violation of meiosis. Embryos are then formed from these teratomas.
“This tumor sometimes even looks like an embryo. It has skulls, teeth, hair and various organs, but it is immature.
In other words, although the embryo is defective, it does not develop with tissues and organs. It can be assumed that if such an egg enters the uterus and attaches to its wall, forming a placenta, then a full-fledged fetus can form from such an egg, ”said Professor Krutovsky.
According to the scientist, in the literature there are regular cases, often unscientific or pseudo-scientific, describing “perfect conception” with the birth of a girl. It is possible that these are insufficiently explored cases of parthenogenesis. Another thing is when they talk about perfect conception with the birth of a child (and this is certainly not in the scientific literature). This is really impossible, because the Y chromosome has nowhere to come from.
Princeless but unnerved
In terms of energy efficiency in social life, parthenogenesis provides undeniable medium-term adaptive benefits for women as it does not require seeking a mate, the associated risks and “energy waste”.
It also seems promising that with the help of artificial parthenogenesis, a woman will have the opportunity to give birth to her own copy – a daughter “as good as herself”.
According to Krutovsky, it is quite possible that technologies have developed enough to make it possible to obtain a “starting factor” for the development of an egg into an embryo using a pill or injection. She took a pill or got an injection – and got pregnant.
Pavel Volchkov, head of the MIPT Genomic Engineering Laboratory, believes the pill is still far away, but the possibility of introducing an edited egg cell that begins to develop into an embryo through IVF already exists at this stage of technology development. However, it is necessary to conduct experiments on primates first and then on human cells.
“The IVF procedure is solved, so I do not understand why I found other ways to give the substance. You can add an additional option for IVF: here, please, parthenogenetic reproduction is also possible, ”said Volchkov socialbites.ca.
According to the scientist, since this has already been done on mice, the probability of successfully transferring the technology to other mammals, including humans, is 99%.
Perhaps the introduction of this technology into clinical practice will mean a gradual shift away from sexual reproduction.
In this case, the world will gradually get rid of men. And the future March 8 will be the feast of the same woman at different ages, who will look at her daughters and grandchildren as if looking in a mirror, and then show in the history books the lost type of a person from the past – men .