Abnormal karyotype!The “special case” of human beings, who look like normal people but never reproduce

2022-06-17 0 By

Childbirth is a natural part of starting a family. Most families consisting of men and women will eventually have a child of their own, who will grow up and educate him.In this process, it not only meets the needs of both men and women as biological reproduction, but also meets the spiritual sense of achievement of parenthood.Although the population of the world is divided into several large groups due to the evolution and migration in history, different groups have certain differences in height, skin color, body proportion, weight, eyes, ears, mouth and nose, etc., in the final analysis, everyone belongs to the human family and can marry and reproduce freely.Even in the remotest jungles, people who still live in a sort of primitive tribe can interbreed with people who live in modern cities.However, human groups are so large that there will always be some unusual individuals.In our daily life, there are some relatively common congenital diseases with chromosomal abnormalities, such as Trisomy 21 syndrome, their intelligence and physical development will be affected, and due to the abnormal number of chromosomes, it may also lead to reproductive cell formation disorders, resulting in the lack of healthy reproductive cells in such people.And modern due to the concept of eugenics and eugenics, such people are generally difficult to find a partner, the rate of their own fertility is relatively low.However, there are still a group of people scattered throughout the human race, whose physical appearance and inner physiology are almost the same as normal people, but after marriage, they have a history of frequent miscarriage or infertility, both male and female.In the process of growing up, because there is no big difference with ordinary people, it is generally difficult to find, many people after marriage due to infertility to go to the hospital for various examinations, and finally found that they are “abnormal karyotype”.Although the phenomenon is scattered, there are a lot of people, and there are not many of them in general.Rumor has it that some of us Chinese have only 22 pairs of chromosomes, but it’s not true. It happens very occasionally.The normal karyotype is 22 autosomal pairs and one sex chromosome pair, and the structure of each chromosome of the two people who combine with each other must be compatible.Lions and tigers, for example, have the same number of chromosomes, body size and reproductive structure, but ligers have a very low probability of being born. It is because of the differences in chromosome structure that the haploid chromosome set of germ cells cannot be perfectly combined into the sister chromosome set.Abnormal karyotypes are similar to this.In fact, human chromosomes are DNA strands and a large number of protein combination, DNA through multiple levels of bending, winding formed an extremely concentrated mass of material.However, chromosomes can also be mutated, resulting in displacement, translocation, inversion, etc., which will lead to the structural recombination of the internal DNA chain.A gene’s chromosomal location may change so dramatically that it cannot match a normal chromosome from another person.In abnormal karyotypes, there is a balanced translocation of chromosomes, which can lead to a large change in chromosome structure or number, but because the genes are flash and function is not changed, people can grow and develop normally.In China, there has been a case of a male in his early 20s, his cell even same-sex chromosomes only 22 pairs of chromosomes, but all functions (except reproduction) are normal.Tests revealed that chromosome 15 was fused to chromosome 14 by a balanced translocation.Such circumstances, both chromosome 14 and 15 of chromosome function are surviving, but overall, he’s only 22 pairs of chromosomes of cells, and there are 23 pairs of chromosomes in normal cells, so that both the formation of reproductive cells, one is the jump chromosome 22, 1 article is 23 chromosomes, it is difficult to combine together to become a sister chromosomes.You can’t reproduce naturally unless you meet an identical translocation of the same chromosome.Abnormal karyotypes can also lead to changes in the structure of chromosomes and make it difficult for germ cells to combine.If placed in the whole human population, this is also a manifestation of human evolution. Human genes and chromosomes are constantly changing, leading to certain differentiation between human populations, just like the modern race of various colors, but the chromosomal differences of various races are not enough to cause fertility problems.But humans are still so numerous that there is always a chance of a single karyotype, a few of which reproduce normally because they find the right mate, and a few who never reproduce.There are many cases of abnormal karyotype in China.But as modern humans, population is very large, the diversity of genes and chromosomes are very difficult to block the entire humanity’s survival and evolution, and with the help of assisted reproductive technology, can be controlled by artificial insemination methods such as giving birth to their children, this also need to pay a price, of course, there are some own produce reproductive cells do not fit,The only way to do that is to take germ cells from the donor, so that the biological parent of the child is not himself.