Recently, a "Scientist for the first time let two male mice give birth: Men have babies are not dreams?" The topic has sparked heated discussions among netizens.
According to media reports, at the 3rd International Summit on Human Genome Editing in London, UK, Professor Katsuhiko Hayashi from Kyushu University in Japan said that his team has achieved the transformation of male mouse somatic cells into egg cells, that is, male XY sex chromosomes into female XX sex chromosomes. Lin said that for the first time, they used the cells of male mice to grow viable eggs, so that the two male mice "produced" offspring.
What exactly is going on with "male rat litters"? What are the breakthroughs and future prospects of this research? How can ethical issues be avoided? On the afternoon of the 11th, a reporter from Red Star News contacted Feng Xuechao, doctoral supervisor and associate professor of the School of Life Sciences of Northeast Normal University, to interpret the study.
↑Related news reports Screenshot from Nature
Revelation:
Male mouse somatic cells become egg cells
Two male mice "give birth" to offspring
With the popularization of gene editing technology, especially molecular scissor technology CRISPR-Cas9, there are more and more ethical and moral controversies about human gene modification. Against this backdrop, the National Academy of Sciences, the National Academy of Medicine, the Chinese Academy of Sciences, and the Royal Society co-hosted the International Summit on Human Gene Editing in Washington to explore the scientific, ethical and social issues raised by human gene editing technology.
At the 3rd International Summit on Human Genome Editing held in London, UK, Professor Katsuhiko Lin's team from Kyushu University in Japan used the cells of male mice to grow viable eggs for the first time, so that two male mice "produced" offspring. It is not difficult to find that the study can be roughly divided into four parts by combing through Nature's reports:
First, the team cultured cells isolated from mice in vitro to turn ordinary cells into pluripotent stem cells (iPSCs) through a technique called "cell reprogramming." In this process, some cells spontaneously lose the Y chromosome, a step similar to mutations in the genetic process.
Feng Xuechao explained that in the biological world reproduction is divided into sexual reproduction and asexual reproduction, of which the biggest advantage of sexual reproduction over asexual reproduction is the ability to create a variation in the process of evolution, "This is produced by species in order to better adapt to external pressure." ”
The second step is to induce these cells that have lost the Y chromosome to double the chromosome through drug action, resulting in male mouse cells with karyotype XX (male mice's natural sex chromosome is XY).
Then, through gene editing technology, the cells are induced to differentiate into egg cells. It can be understood that by adjusting the "program" required for the operation of the cell, the original stem cell is transformed into an egg cell.
Finally, the "egg cell" is cultured with organoids (a cell group grown on a petri dish that resembles a real organ) and in vitro fertilization similar to IVF technology is completed with mouse sperm. These "fertilized eggs" are transplanted into the uterus of female mice to complete development, producing pups.
"This research is relatively simple in principle, and it is actually the application of 'induced stem cells' and the conversion of chromosomes." Feng Xuechao introduced.
In addition, some netizens expressed puzzlement about the experimental operation of "female mice sewn back to back with male rats and share the blood microenvironment during pregnancy", believing that the title of "two male rats giving birth" was exaggerated.
↑ Illustration by Nature
In fact, surgically connecting the circulatory systems of two mice is a common research method, but this technique requires the use of "nude mice", mice that are deprived of immune function, otherwise the mice will die of immune rejection of the blood of other mice. "'Sharing the blood environment' is actually quite difficult because there is rejection. But it is indeed possible. Feng Xuechao said that "two male mice gave birth" is actually a genetic judgment, because the genetic material of the offspring mice, that is, DNA, comes entirely from the two male mice.
Feng Xuechao said that from the practical application point of view, only two male rats can not complete all the process, and it is necessary to have a female mouse surrogacy, "so it is actually not very accurate to say that 'two male rats give birth'." ”
Expert:
The biggest breakthrough was the realization of chromosomal switching
It's "quite difficult" to get on the practical clinical application
"The induction of solid cells into stem cells has been achieved many years ago, and the biggest breakthrough point of this experiment by Japanese scientists is mainly the realization of chromosomal conversion." Feng Xuechao told Red Star News.
Feng Xuechao believes that this research has certain limitations, "it is impossible to copy it to people as it is." On the one hand, the programmed somatic cells developed in the human body are very different, and there are many defects; On the other hand, the success rate of X chromosome conversion is very low. ”
As we all know, the use of biological front-end technology for clinical practice is a rather long process, and the long time here is not only from the difficulty of technical research, but also from the ethical acceptance of the whole society. According to media reports, at the summit, in addition to discussing the latest progress in the treatment of genetic diseases with technologies such as CRISPR/Cas9, researchers also focused on the ethical issues and policy regulation of gene editing technology.
"Subject to the dual pressure of technology and ethics, it is quite difficult for this technology to be applied, especially in clinical applications." Feng Xuechao said.
Professor Lin reportedly said the main motivation for the study was to offer a fertility treatment for couples suffering from infertility, such as women with Turner syndrome who have a copy of the X chromosome that is completely or partially missing.
"If it is used as basic research, this technology is still worth promoting." Feng Xuechao pointed out that if it is to be used in clinical treatment, "through somatic cells derived from women, clinical research on infertility may be more effective." ”
↑ Data with pictures According to Tuworm Creative
Due to the possibility of abuse of artificially created life technology, Feng Xuechao believes that on the one hand, the state needs to "punch hard" in legislation, and only reasonable and progressive laws can promote technological progress, so that science and technology will not become a "Pandora's box"; On the other hand, for researchers, there needs to be awareness, "must consciously resist those technologies that may have a devastating impact on humanity." ”
Professor Wang Haoyi, deputy director of the State Key Laboratory of Stem Cell and Reproductive Biology of the Institute of Zoology, Chinese Academy of Sciences and head of the genetic engineering technology research group, also said in an interview with the media that there is still a long way to go before considering the application of this technology to the clinic.
"Scientists never say never, in principle, experiments have already been done in mice, and of course it is possible to do it in humans. But I can foresee a lot of challenges in the future, and I can't predict how many years it will take (to overcome them). Wang Haoyi said.
Red Star News Reporter Li Wentao Intern Luo Yiwen
Edited by He Xianxian, Editor-in-charge by Feng Lingling
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