Sequential interaction between atoms or molecules of two substances with ...
- The technology tested outside the ocean allows parents having genetic deviations, edit the maternal egg and in the end to have a healthy child.
- Specialists from New York conducted a successful experiment in the Mexican territory, for there are no laws prohibiting this. The method is legalized officially only in the UK.
At the very time, the wonderful birth was held five months ago, but now the specialists considered it possible to declare an event successful. Like all people on the planet Earth, a small boy has a DNA with genes from both parents. However, there is a small fragment of donor DNA in his hereditary code - then you mean, third-person genes. Therefore, with a certain stretch, we can say that the parents have a little Arab not two, and three.
This genetic trick means that the child did not inherit from Mother mutation, which could kill him at an early age. Dad and boy's mom are citizens of Jordan. Well, the technology itself capable of causing an avalanche of disputes was legally approved only in the UK.
Nevertheless, the procedure was carried out by specialists from the United States in the territory where there are no laws at all, for which this experiment could be banned. American embryologists from the New Hope Medical Center (New York) hope that their success will include the green light of an unusual methodology in various countries of the world, which will give the hope of millions of genetically imperfect men and women to acquire normal, healthy offspring, i.e. not to give birth Kids, knowingly doomed to early peril.
For the first time in history, hereditary information from three people allowed the little man again to avoid a terrible disease. And now, doctors know exactly what, reconstructing the maternal egg (and only so, and not somehow otherwise), you can achieve the child to be born healthy.
The parents of the boy, the names of which are not disclosed, have already lost two children due to hereditary disease, which is called Lei syndrome (undercrow necrotic encephalomyopathy). It is a very rare mutation leading to a severe brain striking at a very early age. The first child of the tragic couple died in a six-month age after grave torment, the second - at the age of 8 months. Typically, such children do not live up to 4 years, dying from light insufficiency.
The genes, due to which lei syndrome, were kept in the maternal mitochondrial DNA, which was established during genetic analysis. It is worth noting that mitochondrial genes (and only 37 of them) are never inherited along the father's line.
Depressed by the loss of two offsprings, the spouses went to America, in order to ask for help from the staff of the Center "New Hope", which is engaged in innovation of this kind. Since US laws do not allow genetic manipulations with human mitochondrial DNA, parents and doctors went to Mexico. Doctors removed from the cell core and transplanted it into the devoid of the nucleus donor egg cell, whose mitochondria did not contain genes causing lei syndrome. Then this egg cell was fertilized in vitro spermatozoa of the father of the child.
The specified procedure was repeated five times, and as a result, one of the eggs survived and began to share. So a new life originated.
Doctors write that the possibilities of the tested technique are endless - in the deliverance of human germs from hereditary vices. How far will the specialists go to her use, while it is difficult to say. Still, risks are also quite a lot. But the first step, as they say, is made in full of solid soil.
On the birth of the world's first child "from three parents", which appeared on the light after the pricker transfer. This term means that the baby is a carrier of the DNA of three parents - the main from the father and mother and mitochondrial DNA from a donor woman.
Previously, we recall this kind of technique only to save children from hereditary diseases.
The kid, winning not quite in the usual way, was born on January 5, 2017. His mother became a 34-year-old woman who suffered infertility for 15 years and eventually decided on an important step with her husband. This director of the clinic and genetic doctor Valery Zukin reported at a recent press conference.
Before that, a woman in many local and foreign clinics tried to get pregnant with Eco, but each time the procedure fails. The reason for this doctors was called in this particular case the impossibility of the development of embryos to the thread of blastocysts (this is one of the early stages of the development of the embryo).
That is why the use of donor eggs was the only way to give birth to a child for this married couple. I will explain that after fertilization in the egg, two cell kernels are formed (priducleus) - from mother and from father. Reproductists are withdrawn both of these nuclei from the maternal egg and transfer them to the donor egg, from which two nuclei is also covered before that (it is called enucleated).
Thus, scientists receive "reconstructed" zygota (that is, a fertilized egg), which in this case had a genetic set of about 25 thousand genes from mom and dad and 37 genes from the donor. Therefore, this method is called the birth of "from three parents." It avoids the development of newborn genetic diseases: "unnecessary" genes remain in the source egg, and the genetic material in the nuclei is transferred to the donor cell and remains intact.
When the baby was born, the researchers had many analyzes and confirmed the presence of his genes from three people. This case was the first in his own way, but most likely will not be the only one: in March 2017, the birth of one more baby is expected, conceived by the same way.
The scientific director of the Nadezhda clinic Irina, Irina also noted that the new reproductive method is shown to prevent mitochondrial diseases in the kid under normal conception, and also if for any reason the mother's eggs cannot normally develop in the embryos in the early stages. "There are couples whose embryos have significant chromosomal breakdowns caused by the mitochondria. Such patients also show this method," it added.
Note that mitochondrial diseases are diagnosed by the child only after his birth. They can manifest themselves in severe mental disorders, neuropsychiatric disorders, some forms of cardiomyopathy, violations of violations. Often they lead to the early death of man.
The legislation of Ukraine has not yet regulates the norms of use of such reproductive technologies, but the experiment has received the approval of the relevant ethical committees.
Recall that in September 2016, the first child appeared in Mexico, which would be able to consider parents. True, the technique was used for its conception, somewhat different from the Ukrainian.
Meanwhile, the authorities of the United Kingdom, the procedure for the emergence of children with genetic material from three parents. In the United States also allowed to create children from three parents, but.
In Ukraine, the second in the history of the "child from three parents" appeared on the world ("Three-Parent Baby"). The first such baby was born in September last year in Mexico. What medical experiences and what kind of moms will the child look like?
Ethics or medicine?
Why did the first such children appeared not in New York, for example, and in Mexico City and Kiev - in countries that are not at all leading in the medical world? The answer is simple: because in Mexico and in Ukraine it is not prohibited, such as in the United States. That is why the team of American doctors went to Mexico to carry out the operation there. In Kiev, they made themselves in the clinic of reproductive medicine.
So far, where "production" of such children is authorized officially - the United Kingdom of Great Britain and Northern Ireland. But there are no events hurry and work according to plan. Back in 2015, they stated that they had the first child from three parents closer to the end of 2017. So perhaps the process of its extracorporeal (ECO) conception occurs in London right now.
Normal development
To understand that the child receives from each of the parents, you need to see how this happens in the usual, natural way. When the spermatozoid fertilizes the egg, the kernel of both sex cells in which the DNA is linked. As a result, the future child inherits 50% of genes (it is essentially DNA) from the father and the same amount from the mother.
But besides this hereditary information contained in the core of the cells, there are some more DNA in mitochondria. These are electrical cells of cells producing energy and freely floating outside the nucleus - in the cytoplasm of the cell. In this DNA, information is encrypted, which is important for mitochondria - it depends on it, like how much they will produce energies and how it will be used.
This is important for athletes: there are mitochondria ideal for sprinters and for styers. There are mitochondria with which people are better not to play sports at all. There are diseases of mitochondria in which the child develops poorly. First of all, he suffers from the brain and muscles. With severe changes, for example, with lei syndrome, children do not usually live up to 1-2 years. So it was the woman who was the first to endure and gave birth to a child from three parents - she died several children.
But it is important that mitochondrial DNA does not affect our appearance, character, behavior. And it is still extremely important that this DNA is transmitted to the child only from the mother - 100 percent. Why? From the Father, he receives one core, and all other parts of the sperm, including mitochondria with DNA, go into waste. And the basis for the development of the future child is always an egg, it is she who after fertilization begins to share, forming an embryo. And on the basis of its mitochondria, the mitochondria of the future child is formed.
Combination of three elements
In order to get rid of the mitochondria from defective DNA, and the second mother is needed - a donor with normal healthy mitochondria. How it works? Imagine a combination of three elements.
1. Mother eggs
2. Female donor eggs with healthy mitochondria
3. Sperm Father
And then you need to make it so that the basis of the future child's development has become an egg-donor egg egg cell, but devoid of kernel. Instead, it is necessary to put the nuclear DNA of Mother and Father. As a result, the child will receive almost all heredity from his parents, and only DNA mitochondria is from the donor.
As they did in Mexico, Peter Chumakov explains, Professor, Doctor of Biological Sciences, I.O. Head of the Proliferation Laboratory of Cells of the Institute of Molecular Biology. V.A. Engangardt: "In order for mitochondria from DNA from the maternal egg, they did not get to the child, they did so. The kernel was taken out of her, and they were replaced by a donor egg core, after which it feared her spermatozoa father. That is, a genetically child inherits all signs of their parents who are encoded in the kernel. In addition to mitochondria, which autonomously multiply in the cytoplasm and come from the donor. It is important that, in principle, the method is simple and in laboratory conditions well-worked. It is still not yet clear how a small number of mother patients will continue to behave further, which are inevitably recorded when core transplant. Will they define healthy donors? But while the child is healthy. And, of course, this is not cloning, and no fertilized eggs and embryos died during the procedure. That is, ethically, this is quite acceptable procedure. "
What did you do in Ukraine
Father's spermatozoa fertilized both egg cells - maternal and donor. Then, from the donor cell, the kernel was removed, replacing it with an already fertilized kernel from the maternal cell. And she already contributed to the mother of the mother, as it usually happens when Eco. In this case, from two fertilized eggs, only one, becoming hybrid, received further development. In principle, this can cause criticism and impede such manipulations in many countries.
According to Ukrainian doctors, in March in Kiev, they are waiting for the birth of a second child from three parents. As stated, pregnancy is normal. Another feature of Kievans is that they are not connected with the early death of children born with mitochondrial defects, but with infertility and the inability of women to endure a child. They had multiple miscarriages after ECO - the embryo did not develop and died. This may also be associated with damage to mitochondria, because their energy is needed for intrauterine development.
Mitochondria model in context
Gregory Han / Flickr
Ukrainian Reproductologists told about the birth of the first child in the country with DNA of three parents - the main from the father with his mother and mitochondrial from a woman donor, UNIAN reports.
The procedure of mitochondrial substitution therapy (MZT), which was held by the Nadiya clinic, aimed at the birth of healthy children in women who suffer from mitochondrial defects. There are two MZT methods. One of them is that the kernel of the mother's egg cells containing the main genetic material is transplanted into the donor egg cell with a pre-remote kernel, after which it fell fertilized by her father's sperm. As a result of such a procedure conducted by the New York Clinic NEW Hope in the Mexican Guadalajara, in the summer of 2016, the first child from three parents.
The second method that Ukrainian doctors were used for the first time in the world, is that the maternal egg with defective mitochondria is first fertilized, and then transferred to the donor egg core to the deprived nucleus, already containing DNA of both parents (such a technique is called pricker transfer). In both cases, the resulting embryo is placed in the mother's uterus for napping, as with the usual elecorporal fertilization procedure (ECO).
"With the help of priedarial transfer of nuclei, a 34-year-old woman with infertility for 15 years could give birth to a healthy genetically" his native "child. For many years she tried to get pregnant with the help of the ECO method in the Ukrainian and Israeli clinics. In early January, "our" child was born. For the first time in Ukraine, the reproductologists of the clinic "Nadezhda" managed to reach pregnancy thanks to the priedrian transfer of the nuclei of the parents into an enucleated (deprived of his own nucleus) donor eggs, "said Valery Zukin at a press conference. According to him, the presence of a DNA child from three people was confirmed by analyzes conducted in the laboratories of Ukraine and Germany.
Earlier at the World Congress on Reproductive Technology ART 2016. In New York, Zukin said that the MZT method of pricker transfer was held two of his patients who have no hereditary diseases of mitochondria, but due to mitochondrial insufficiency they had miscarriages in early terms.
Currently, the MW procedure is officially permitted only in the UK, although such experiments have not yet been conducted there. In most countries, this issue is currently not regulated. Experiments in Mexico and Ukraine received the approval of the relevant ethical committees.
Nevertheless, the holding of MW is systematically criticized by experts. They are concerned about the lack of data on the effectiveness and security of this procedure for the child and its future offspring. Also repeatedly sounded calls to carry out MZT only male embryos, because men do not convey their mitochondria to offspring. At the same time, one of the patients of Sekin, as reported, is pregnant with a girl (Paul born child in a note is not specified).
A boy born by New Hope employees is healthy and feels good. Also, according to Natur.e, a child from three parents was born in China, and the publication dedicated to this is now on reviewing in one of the scientific journals.
In the news only talk about the birth of the first child through very controversial genetic technology, with which it may be possible to avoid transmitting potentially fatal hereditary disease. In addition to the direct expansion of the limit of the possibilities by the method of extracorporeal fertilization, this technique gained fame since it allows the child to have three genetic parents immediately. They report that the little boy, the progress was covered in a similar way, was born 5 months ago, the conception itself was produced in Mexico by a specialist from New York due to less hard rules regarding manipulations with human embryos in this country than in the United States, where they refused to give permission For the experiment.
Until now, we are not known all the details. The New Scientist was published, Dr. John Zhang, from the center "New Nadezhda Fertility" in New York, holding a newborn in New York, who told the history of the family of this child. The spouses lost two senior children from the mitochondrial disease, a very rare state caused by a defect in the Mitochondrial - organellah DNA, which provide the cell cells of the energy. Babies inherit mitochondrial DNA from the mother, and if the mother is a carrier of mutation in this DNA, a wide variety of life-threatening states can simply kill newborns.
Zhang, as reported, used the method called the targeted transfer of the kernel, with which it is possible to create five human embryos at once. The method includes the removal of the nucleus - and, accordingly, most of the DNA of one mother's egg cell, and the introduction of this kernel into the donor egg cell, devoid of its own nucleus. The result is an egg with mitochondrial DNA from a healthy donor and nuclear DNA from the mother. Five donor eggs prepared in this way were fertilized by a sperm of her husband, but only one of the embryos had a normal chromosome. This embryo was put into the mother's body.
Zhang agreed to give an additional interview ("For us, the patient's desire for us is explained by the employee of the marketing department" Science ") & but many scientists were concerned about the way the Zhang team reported on the development, as well as the fact that the experiment took place in a negligible experiment supervision.
In addition to what was published in New Scientist, another source of information is devoted to the details of the negotiations, which are planned at the October meeting of the American Society of Reproductive Medicine. According to annotation, in 3 months the health of the child did not cause any concerns, but nevertheless the most affected mitochondrial DNA DNA still remains about 1% -2% of the cells studied by the cells of the newborn. Nevertheless, this child has no clinical manifestations of lei syndrome - a disease that has already killed his brother and sister.
Limited information in the article left a large number of questions. "Now it's just" We did it, exactly what was waiting for us, "says Dieter Egle, a biologist engaged in learning stem cells in Columbia University. Without an answer, issues of the presence and reaction of an ethical committee on the process of extracorporeal fertilization remain. (The article mention that the Council after reviewing the problem approved the experiment, only the fact that was happening - in Mexico, or somewhere else), what further medical observation will receive a child, for the first time a group of researchers used this technology And whether there will be more such attempts. "These and other important questions remain unanswered because this work was not published, therefore the rest of the scientific community could not consider it in detail" - writes Dukhoko Ilch, a scientific journalist specializing in stem cells in the Royal College of London - "extremely important, What would this happen in the near future. "
Norbert Glyahercher, a fertility specialist in the center of the man's reproduction in New York, reports that the decision of the New York team about work in Mexico is quite expected to consider all the obstacles to attempts to such an experiment or even submit an application for approval of a proposal in the United States. Glyahercher tells that one day he was looking for meetings with the Association of US drugs to discuss the methodology for replacing mitochondrial DNA for patients of the country, including as a means for treating infertility. "We could not even get to the reception," he admits.
The United Kingdom, as well as the American National Academy of Sciences, has given its confirmation of the possibility of the existence of the theory of mitochondrial transmission, in order to prevent the disease. However, in the United States, Congress banned the association of drugs any experimental treatments. "The situation of regulation of anything in the United States is something that does not make any sense," says Glyahercher - "You yourself are witnessing what we have results - in fact, this is an experiment that moves forward without any supervision."
Egley agrees. "It is important for me that the regulators, such as the drug association, are also moving forward," he said. "After all, then it could be done and scientists with groups of the United States, who have for many years and even decades of research experience."
Clinical embryologist Jacques Cohen from the Institute of Reproductive Genetics in Livingston, New Jersey, who just gave advice to the Zhang team on how it is better to solve regulatory issues, defends its decision to fulfill the procedure in Mexico due to the presence of limitations from the United States. "Simply because it was done in Mexico does not mean that this was done without a ethical look at the problem," says Cohen, who himself led ambiguous fertility experiments in the 19990s associated with the movement of cytoplasm, in the results of which infants Also had three genetic parents.
Zhang is not a newcomer in the embryo modification technique. In 2003, he already did something similar in China, moving the core from one egg to another, although in this case the egg cell was also fertilized. The news was published, including the "The New York Times", but the research work describing this experiment appeared only last month, in InreProductive Biomedicine Online. As a result of an experiment, a 30-year-old woman became pregnant, but both of her twins died before birth.
In 2009, the Group under the leadership of the Shukrat Mitalipov from the University of Oregon "Health and Science" in Portland, revived the debate on the mitochondrial substitution therapy in connection with the receipt of successful results in the Macak. Like others, Mitalipov with anxiety spoke in his statement in "Science" that the desperate parents were simply forced to leave for countries with less control. He attributed control to the Congress, which prevents the association of drugs in the resolution of the mitochondrial substitution procedure.
