Parthenogenesis is a technique of immaculate conception. Parthenogenesis: undivided motherhood

Parthenogenesis (Parthenogenesis - from the Greek parthenos - girl, virgin + genesis - generation) is a form of sexual reproduction in which the development of an organism occurs from a female reproductive cell (egg) without fertilization by a male one (sperm).

Parthenogenesis should be distinguished from asexual reproduction when development occurs not from germ cells, but from somatic cells or organs by division, budding.

This is sexual, but unisexual reproduction, which arose in the process of the evolution of organisms in dioecious forms. In cases where parthenogenetic species are represented only by females, one of the main biological advantages of parthenogenesis is the acceleration of the rate of reproduction of the species, since all individuals of such species are capable of leaving offspring. If a female develops from fertilized eggs, and a male from unfertilized eggs, parthenogenesis contributes to the regulation of the number and sex ratio (for example, in bees, males - drones - develop parthenogenetically, and from fertilized eggs - females - queens and worker bees).

Parthenogenesis- natural normal way reproduction of some species of animals and plants. Complete natural parthenogenesis occurs in invertebrate animals of all types, but most often in arthropods. Among vertebrates, these are fish, some species of amphibians, reptiles individual species birds (turkeys) reproduce parthenogenetically. In mammals, only cases of embryonic parthenogenesis are known, isolated cases full development observed in rabbits during artificial parthenogenesis. In humans, there are known cases when, under the influence of stressful situations of high temperatures and in other extreme situations, a female egg can begin to divide, even if it is not fertilized, but in 99.9% of cases it soon dies (according to some data, 16 cases of immaculate conception were known in history place in Africa and European countries).

Parthenogenesis can be obligate, when eggs are capable only of parthenogenetic development, and facultative, in which eggs can develop both through parthenogenesis and as a result of fertilization (in bees). Often reproduction through parthenogenesis alternates with bisexual reproduction - the so-called cyclic parthenogenesis. So, in some species of aphids, two-fingered generations (winged forms) are replaced by parthenogenetic (wingless females), while different generations use different types fodder plants.

Parthenogenetically, either an egg cell that has undergone meiosis and contains haploid set chromosome(n) (generative, haploid, or meiotic parthenogenetic), or an egg cell of one of the premeiotic stages of oogenesis with preservation of the characteristic this species chromosome set - diploid (2n) or polyploid (3n, 4n, 5n, rarely 6n, 8n) (ameiotic parthenogenesis). In some forms of parthenogenesis, the fusion of the haploid nucleus of the egg with the haploid nucleus of the directional (polar) body leads to restoration of diploidity (automictic parthenogenesis). The genotype, sex of the parthenogenetic offspring, as well as the preservation or loss of heterozygosity, acquisition of homozygosity, etc., depend on these features of parthenogenesis.

Artificial parthenogenesis in animals was first obtained by the Russian zoologist A. A. Tikhomirov in 1886 by exposing unfertilized silkworm eggs to various physicochemical stimuli (solutions of strong acids, friction, etc.). Artificial parthenogenesis was subsequently obtained by J. Le Bon et al. . studied in many animals, for example, in marine invertebrates ( sea ​​urchins, stars, worms, mollusks), as well as in some amphibians (frogs), and even in mammals.

Artificial parthenogenesis is caused by action on eggs hypertonic solution(hypotonic - osmotic parthenogenesis), injection of an egg with a needle moistened with hemolymph (the so-called Traumatic parthenogenesis of amphibians), sudden heating or cooling (Temperature parthenogenesis), as well as the action of acids, alkalis, etc.

With the help of artificial parthenogenesis it is usually possible to obtain only initial stages development of the organism, complete parthenogenesis is rarely achieved.

The method of mass parthenogenesis was developed for the silkworm in 1936 by B. L. Astaurov. This method is based on precisely dosed short-term heating (up to 46oC for 18 minutes) of unfertilized eggs removed from the female. The method makes it possible to obtain only female individuals, hereditarily identical with the maternal female (initial), as well as similar to each other, giving an increased yield of silk fiber highest quality.

Parthenogenesis also includes peculiar methods of development of animals and plants - gynogenesis and androgenesis, in which eggs are activated for development by penetrating sperm of their own or a similar species, but the nuclei of the egg and sperm do not merge. Fertilization turns out to be false, and the embryo develops with only a female (gynogenesis) or only a male (androgenesis) nucleus.

Thus, if American scientists’ experiment ends successfully, that is, healthy baby macaques are born, then experiments with human eggs will probably begin soon, especially since there are enough female volunteers.

Infertile and lesbian couples are most interested in this. However, they must take into account that only girls can be born. For now, scientists do not intend to conduct similar experiments on people, since there is a serious risk of developing cancer diseases and metabolic disorders in newborns, as well as the fact that we have genes that only work if they are received from the father. It is in them that the proteins necessary for the development of tissues and organs are encoded. Therefore, it is unlikely that women will be able to do without men, at least in the near future, while man is not able to outwit nature.

I found a topic, and I googled a little more :) look what scientists are approaching now:

Immaculate Conception or Parthenogenesis

“Parthenogenesis” is virgin reproduction in which a female egg develops without fertilization, that is, without the participation of a male being. Biologists have long discovered that virgin birth is not uncommon in the animal world. Many invertebrate animals reproduce in this way, and in some cases, some species of birds and lizards. This saves the species from extinction if for some reason there is not a single male specimen nearby.
In total, there are 16 known cases of immaculate conception in humans that occurred in Africa and European countries.

Version one

In southern Italy in the XVI - XVII centuries there was a convent where one or two nuns found themselves in prison once every five years interesting position. Whatever the local bishop came up with. He evicted peasants from surrounding villages under 60 years of age, forced the poor things to wear chastity belts - nothing helped. The nuns who became pregnant were not as lucky as the Virgin Mary, and every conceivable sin was blamed on them, the basis of which was a connection with the devil. And finally, when in one year a scandal occurred with three brides of Christ at once, the authorities transferred the monastery to a more safe place, declaring that territory subject to the Prince of Darkness.

Another example from today. There was a supermarket in Glasgow with 15 checkout counters at the exit. And so those ladies who were sitting for the seventh in a row regularly became pregnant, whether they wanted it or not, whether they used contraceptives or not. Moreover, among those who find themselves in awkward situation The women included both those who turned out to be virgins and those whom doctors sentenced to permanent infertility. The administration initially brushed aside the complaints of dissatisfied ladies. But the newspapers found out about the situation, and the owners invited scientists. Moreover, some women did not sit down at the seventh cash register even under the threat of dismissal, while among others a queue formed, which, admittedly, moved quite intensively. Despite the participation of men in the process, 90% of the women in the queue gave birth to girls. Scientists from leading universities in England, having examined all the women sitting at the ill-fated cash register, could not say anything sensible. And the ritual of exorcism, carried out by priests of the Protestant and Catholic branches of Christianity, also had no effect.

It has long been recorded that in animals, rhythmic mechanical vibrations can cause spontaneous division of the egg, without the participation of the sperm. And it even seems that somewhere they managed to reproduce this effect on monkeys. Naturally, this kind of experimentation on humans is prohibited.

So, nuns in the south of Italy lived near an active volcano, where the earth periodically vibrated, and not far from the ill-fated supermarket, a Japanese concrete mixer with very low vibration wave characteristics periodically worked. This device was rigidly attached to the asphalt, and the wave of vibration was directed directly to cash desk No. 7...

To be fair, it should be noted that all of this is nothing more than speculation, and much of it doesn’t add up. First of all, during parthenogenesis new organism does not receive additional genetic information and, therefore, is a copy of the mother. That is, all those born supposedly in this way should be girls. And among women who became mothers in this way, boys were also observed. By the way, when the construction near the supermarket was finally completed, the effect disappeared...

Version two

Forensic experts know well that when stressful situations, the influence of high temperatures and in other extreme situations, a female egg can begin to divide, even if it is not fertilized. Some scientists even argue that if a woman is predisposed, then it may be enough for her, for example, just to take a long steam in a bathhouse, and the egg will begin to turn into an organism. True, most likely, she will die soon.

An egg ready for fertilization contains 23 sex-bearing chromosomes. During the “immaculate conception,” 23 female chromosomes, ripe for fertilization, are divided into two halves each, and 46 chromosomes necessary for a new life are formed in the egg. After this, the egg can begin to split and develop into an embryo, which is exclusively female.

Doctors believe that these “miracles” are caused by a bacterium that usually lives in the bodies of insects, but can move into a person, stimulating the division of the egg and forming an embryo. The bacterium destroys male embryos or turns them into female ones.

There have already been many cases of changes in the sex of the embryo in people who have experienced extreme situations or living in hot climates, and the male sex of the embryo always changes to female, and never vice versa. There is a version that the bacterium can live in the human body for a long time and become more active under the influence of high temperature, for example, when visiting a bathhouse or sauna.

But the “immaculate conception” is a phenomenon so unstudied that, at times, it is confused with the most “vicious” thing. For example, there are many known cases where virgins became pregnant without sexual intercourse, for example, after petting, when the partner’s sperm got on the genitals. Getting pregnant this way is difficult, but possible - the most “dexterous” sperm are able to penetrate a woman through the hole in the hymen and reach the egg, covering a distance of about 10 cm! Some become pregnant without a man at all - by sitting on the place where the seminal fluid was located, or by wiping off with a towel with traces of sperm.

Immaculate Conception. The mysterious word "parthenogenesis"

Previously, very little was known about this phenomenon. In any case, the word itself appeared quite recently. And before that there was only the story of the Virgin Mary and the Immaculate Conception. It would never have occurred to anyone to compare this story with normal pregnancy, Christians perceived this phenomenon as a miracle, and non-believers considered it a legend.

The concept of parthenogenesis

During fertilization, the sperm releases the egg from its dormant state and it begins to develop. But in nature there are cases when an organism developed from an unfertilized egg.

Definition 1

The phenomenon of development of an organism from an unfertilized egg is called parthenogenesis .

In the case of parthenogenesis, the new generation has an unchanged parental genotype. In some species, both parthenogenetic and bisexual populations can exist (in lizards). For other species, parthenogenesis is the only way reproduction (in stick insects). In ground beetles and daphnia, sexual and parthenogenetic generations naturally alternate.

Some scientists believe parthenogenesis separate form asexual reproduction, since there is no sexual process (copulation). Others consider it a variant of sexual reproduction, since it is the germ cells that take part in it.

Diploid parthenogenesis

There are a number of animal species in which unfertilized eggs develop over a certain period. In the nucleus of the egg, the number of chromosomes doubles and they become diploid (or meiosis does not occur during the formation of the egg).

Example 1

For example, in the above-mentioned ground beetles and daphnia, throughout spring, summer, and early autumn (that is, most of the year), reproduction occurs only parthenogenetically. Only females develop from unfertilized eggs. In autumn, males appear and the process of fertilization occurs. Fertilized eggs survive the winter. In the spring, they again develop into females capable of parthenogenetic reproduction.

Diploid parthenogenesis contributes to the rapid reproduction of populations of these species.

Haploid parthenogenesis

In bees and some other insects, females develop from fertilized eggs. From them, workers (underdeveloped females) and queens are formed. Drones (parthenogenetic males) develop from unfertilized eggs. Male cells have a haploid set of chromosomes. During the formation of sperm, meiosis does not occur and the number of chromosomes in sperm does not decrease. Therefore, during fertilization, organisms receive diploid set chromosomes.

Artificial parthenogenesis

During research, embryologists were able to stimulate the development of an egg without fertilization. They used certain stimuli as a stimulating factor (chemical, mechanical or short-term influences of high or low temperatures etc.). The influence of these stimuli contributed to the excitation of the egg and the beginning of the formation of fertilization membranes.

Note 1

The phenomenon of artificial parthenogenesis is actively used, for example, to regulate the sex of silkworms in sericulture.

Androgenesis

There are cases in science when the nucleus of an egg was destroyed. At the same time, the egg itself retained the ability to fertilize. Then the sperm nucleus occupied central position in the egg. The egg developed further parthenogenetically, but with a sperm nucleus. The resulting new organism had only paternal characteristics. This phenomenon is called in science androgenesis .

The phenomenon of parthenogenesis probably arose as a reaction of the body to sudden changes in environmental conditions. These changes led to the impossibility of fertilization. Therefore, individuals survived. In which the egg began to develop independently. This adaptation allowed the species to survive in unusual and changing conditions. The parthenogenesis method can be very useful in breeding work.

The term "immaculate conception" is widely used in both religious and fiction. However, the possibility of this phenomenon in ordinary life until recently it was completely denied. Is it really? To answer the question, you need to understand the main stages and conditions of conception.

Conception

In medicine, conception is understood as the fusion of two germ cells. They are the ones who give rise to the embryo. Regular cell human body contains 46 chromosomes. In contrast, in the sexual, this set is halved - to 23.

22 of them are called autosomes and only one is called a sex chromosome. It can be X or Y. The first is responsible for the female gender, the second for the male.

When the egg and sperm merge, the half sets are combined, and subsequently all the cells of the embryo carry 46 chromosomes, which are called a karyotype.

All eggs carry the X chromosome. With sperm the situation is different. Half of them contain an X chromosome, and the other half contain a Y chromosome. The cell formed after fertilization with a set of XX will lead to the birth of a girl, XY - a boy.

For a person, the participation of a man and a woman is mandatory in the process of conception, which is why in religion it is considered vicious. After all, sexual intercourse is closely connected with the concepts of sinfulness and vice.

Immaculate Conception

In contrast to ordinary conception, virgin conception means one for which the participation of a man is not necessary. Its second name is seedless.

A striking example of the virgin birth is the birth of Jesus Christ, described in the Bible. It lies at the core of the concept of Christian theology.

From a medical point of view, such reproduction is devoid of practical meaning, since in this case the fetus inherits all the characteristics of the mother and is her copy. This means that the variability of the human body will be impossible in principle, and after it, adaptation to changing conditions external environment and survival of the fittest organism.

The existence of people with the same genotype will sooner or later lead to their extinction. After all, spontaneous mutations in genes occur constantly, and they will be inherited by each subsequent child.

However, both in nature and in science today, the immaculate conception is found. Its main options can be distinguished:

• Parthenogenesis.
• Cloning.

Parthenogenesis

Parthenogenesis is a sexual type of reproduction that does not require the participation of a male individual. Thus, it can be considered scientific name Immaculate Conception.

This type of reproduction occurs in many insects, invertebrates, and even some vertebrates (such as lizards). Exist various options and mechanisms of parthenogenesis.

Often, both parthenogenesis and normal conception occur within the same species. A striking representative of such reproduction are bees, the males of which develop from unfertilized eggs, and the females from fertilized eggs.

However, for mammals (and humans, in particular), conception in the form of parthenogenesis is not typical in ordinary life. But in the laboratory, scientists managed to achieve some success.

Artificial parthenogenesis

Scientists have repeatedly conducted various experiments to study parthenogenesis.

It was noted that when the egg was irritated, it began to spontaneously divide and even turned into a so-called blastocyst - one of the early preimplantation stages that a human embryo goes through. However, cell death inevitably followed.

The culprit for this, according to scientists, is considered to be genomic imprinting - a special mechanism that regulates the degree of influence of certain genes on the development process of the embryo. Thus, the genes of a male individual are more responsible for the formation and development of the placenta, while female genes influence the embryo itself.

Thus, it becomes clear that, even if under the influence of any stimulus (including severe stress) the woman’s egg will begin to divide spontaneously, such an “embryo” will still not be able to implant.

To date, genomic imprinting has been defeated only in experiments with mice.

Experiment with turning off imprinting

In April 2004, a mouse named Kaguya became famous in Japan. She turned out to be the first mammal to be the offspring of two mothers. Their eggs united and developed into a full-fledged embryo, the pregnancy progressed and ended with the birth of a healthy mouse.

However, this turned out to be possible only in laboratory conditions. In one of the eggs, some DNA fragments were removed, which made it possible to neutralize the influence of genomic imprinting and achieve normal development embryo.

Kaguya turned out to be a classic example of the virgin, or seedless, conception. She inherited genetic traits both mothers. Subsequently - after the usual crossing with a male - this mouse gave birth to healthy offspring.

Similar experiments with female eggs not currently carried out.

Cloning

Cloning can only conditionally be classified as a variant of the immaculate conception. The fact is that this process is a type of asexual reproduction and is impossible in highly organized organisms without human intervention.

When cloning, the body of an individual is recreated in whole or in part. The most famous clone is a sheep named Dolly, which was copied from the cell of another adult.

This method, in theory, makes it possible to restore rare and extinct animal species. In addition, it can be successfully used in medicine, where the reconstruction of organs is needed.

Cloning of living or dead people is a serious problem today ethical problem in medicine.

Real cases

Is the virgin birth even possible? Are there real cases confirmed by doctors and scientists?

To date, all known cases of immaculate conception in humans are considered fiction. You can find many stories on the Internet dedicated to this phenomenon, but all of them cannot bear the slightest criticism.

Most often, the immaculate conception refers to the pregnancy of a virgin. Such cases do happen and are not even uncommon. Sooner or later they are encountered in the practice of any obstetrician-gynecologist.

However, they are always easy to explain. The development of pregnancy in a woman with an intact hymen is possible in two cases:

1. When sperm enters the vagina without full insertion of the penis. This happens during petting and other tricks or sexual games.
2. With a dense hymen, as a result of which defloration does not occur. As a rule, a woman ceases to be a formal virgin only after childbirth.

However, these situations have no connection with the immaculate conception, since male sperm are involved in the fertilization of the egg.

Immaculate conception in humans today is impossible under any circumstances.

Parthenogenesis is also called virgin reproduction; this process is typical for species that have a short life cycle accompanied by pronounced seasonal changes.

Androgenesis and gynogenesis

During the process of adrogenesis, female sex cell does not take part in the development of a new organism, which appears as a result of the fusion of two nuclei of male germ cells - sperm. In this case, only males are present in the offspring. In nature, androgenesis occurs in hymenopteran insects.

During gynogenesis, the sperm nucleus does not merge with the egg nucleus; it can only stimulate its development, so-called false fertilization occurs. This process is characteristic of bony fish and roundworms, while the offspring consists only of females.

Haploid and diploid parthenogenesis

In haploid parthenogenesis, an organism develops from a haploid egg, and individuals can be female, male, or both, depending on the chromosomal sex determination of the species. In ants, bees and wasps, as a result of parthenogenesis, males emerge from unfertilized eggs, and females from fertilized eggs. Thanks to this, organisms are divided into castes; the process allows you to regulate the number of descendants of a certain type.

In some lizards, aphids and rotifers, diploid parthenogenesis is observed; it is also called somatic. In this case, diploid eggs are formed in females. This process makes it possible to maintain the number of individuals if the meeting of individuals of different sexes is difficult.

Natural and artificial parthenogenesis

Parthenogenesis is cyclical in rotifers, aphids and daphnia. In the summer, only females exist; they develop parthenogenetically, and in the fall, reproduction occurs with fertilization.

Parthenogenesis can be induced artificially, for example, by irritating the surface of silkworm eggs, heating or exposure various acids, it is possible to achieve egg fragmentation without fertilization. It was possible to obtain adult rabbits and frogs parthenogenetically.