1. What is the effect of chromosome aberration?
The abnormal changes of chromosomes in somatic cells or sex cells are called chromosome aberrations, which can be divided into two categories: quantitative aberrations and structural aberrations. Chromosome aberration of fertilized eggs is an important cause of stillbirth or chromosomal diseases. ?
Chromosome number aberration can be divided into two types: one is the increase or decrease of the whole chromosome number in the cell, which leads to aneuploidy changes; The other is that the number of chromosomes in the cell increases or decreases 1 or several, causing aneuploid changes. Although it is rare for fertilized eggs to become live babies due to ploidy changes, it is also common in children with spontaneous abortion with chromosome aberration (about 22%), indicating that polyploid fertilized eggs are not very rare. Aneuploid changes are also common in abortion and stillbirth. ?
The change of chromosome structure essentially refers to the increase or decrease of 20 kinds of genetic material on chromosome or the change of position. Any kind of structural distortion is related to chromosome breakage and reconnection after breakage. Chromosome structural distortion is also an important cause of chromosome diseases. ?
Because a certain number of genes are arranged on chromosomes in a certain order, and the number and structure of chromosomes have changed for some internal or external reasons, it will cause abnormal structure and function of the body, which is called chromosome cheek. Because chromosome aberration usually involves a wide range, and because of the pleiotropy of genes, chromosome diseases often involve morphological and functional abnormalities of many organ systems. Clinical manifestations are often varied, often manifested as syndrome. The common clinical symptoms are multiple deformities, growth retardation and mental retardation. Sexual dysfunction is also common. In addition, we can also see the texture changes of leather instruments. Chromosome aberration can also lead to fetal abortion and stillbirth. In the first three months of pregnancy, 65% of children with spontaneous abortion have chromosomal abnormalities, and 20% of all children with spontaneous abortion have chromosomal abnormalities. At present, there are more than 10,000 kinds of abnormal numbers or structural aberrations of human chromosomes, involving almost every chromosome. One hundred kinds of chromosome syndromes have been identified, including common chromosome diseases and sex chromosome diseases involving sex chromosomes. ?
Second, the inducement of gene mutation?
All living things in nature will have gene mutation constantly, and the mutation under natural conditions is called natural mutation or spontaneous mutation; Mutation induced by some physical and chemical factors is called induced mutation. No matter what kind of mutation, it can lead to the production of new genes and the formation of new traits. The cause of spontaneous mutation is still unclear, which may be related to external factors and internal factors. External factors mainly refer to natural radiation, such as cosmic rays. Internal cause refers to radioactive carbon and strong acid in human body; Extreme changes in temperature, chemicals, substances and substances produced in some physiological and biochemical processes. The factors inducing mutation are:?
Physical inducing factors; Including X-ray red, alpha-ray, R-ray, neutron, proton and so on. The greater the energy contained in the radiation, the higher the induction efficiency. Radioactive substances are very harmful to human body. In the 1920s, some women workers who made night dishes often licked and sucked the pen tips made of radioactive radium with their tongues, and finally most of them suffered from leukemia and bone cancer. Among the survivors after the atomic bomb explosion, the closer to the explosion center, the higher the chromosome aberration rate and the greater the possibility of suffering from hemophilia. ?
Chemical mutagenic factors: including modern industrial waste gas, industrial reactants and raw materials, levofloxacin in catering industry, medicine and pesticides. Both have induced effects. Like contact with SO? (2) The abnormal rate of blood lymphocytes in workers polluted by gas increased obviously; Nitrite can cause gene mutation and cause cancer. ?
Biological mutagenic factors; Biological mutagenic factors mainly refer to viruses, such as measles virus, rubella virus and scar rash virus. Its toxins and by-products such as aflatoxin have induced effects. ?
Third, the impact of gene development on health?
From the birth of new life to the death of aging, it has experienced a complex and changeable environment, first of all, the generation and combination of parental germ cells, then the growth and development of zygotes, and finally become a person with parental genetic traits. The expression of traits is controlled by genetic materials (genes). If the genetic gene changes, it will lead to the abnormality of the determined traits and produce various types of genetic diseases. ?
1? What are the characteristics of genetic diseases?
Hereditary diseases are diseases caused by abnormal changes of genetic material in human germ cells or fertilized eggs. It is a disease that seriously harms people's health and has the following characteristics. ?
(1) Hereditary and familial?
After the patient passed on the pathogenic gene to the next generation, many members of the family became ill. ?
(2) congenital?
Because the pathogenic gene exists at the time of fertilization, it is congenital. Some have developed diseases in the early stage of fetal development, leading to partial spontaneous abortion; Some begin to get sick after birth; There are also young people or adults who get sick, such as diabetes and essential hypertension. ?
(3) for life?
Most genetic diseases are lifelong, which often puts a heavy burden on families suffering for life. Even after treatment, they can still be passed on to future generations through pathogenic genes. ?
(4) It occurs at a certain rate in the population?
In a certain ethnic group, all kinds of genetic diseases have their own incidence. ?
2? What are the types of genetic diseases?
There are three kinds of human genetic diseases, namely monogenic genetic diseases, polygenic genetic diseases and chromosomal aberrations. ?
(1) Single gene hereditary disease?
This is due to a single gene suddenly. There are more than 4,000 known genetic diseases of this kind, which can be divided into the following four types according to different genetic modes:
① Autosomal dominant genetic diseases: such as polydactyly, syndactyly, short stature, multiple colonic polyps, neurofibroma, skull hypoplasia, spherocytosis and ichthyosis. ?
② Autosomal recessive genetic diseases: such as albinism, congenital deafness's disease, galactosemia, phenylketonuria, infantile muscular atrophy, cystinuria and other diseases. ?
③X chromosome linked dominant genetic diseases: such as vitamin D-resistant rickets, hereditary inflammation, pigmentary incontinence and other diseases. ?
④X chromosome linked recessive genetic diseases: such as red-green color blindness, hemophilia, pill feminization syndrome, X-linked ichthyosis, X-linked spinal muscular atrophy, self-destructive appearance syndrome, etc. ?
(2) Polygenic genetic diseases?
This is because many genetic diseases are determined by genes, which often show different conditions from mild to severe, such as essential hypertension, asthma, diabetes, coronary heart disease and so on. Most of these genetic diseases have a high incidence rate (1% ~ 5%), which is a common disease with serious harm, but the incidence rate is low among the patients' compatriots, which is easy to be ignored and mistaken for non-genetic diseases. Dozens of such diseases are known. ?
(3) Chromosome aberration?
This is because the patient's chromosome number or structure is abnormal. Such as congenital dementia (tongue coating dementia), super girl syndrome and various malformations, there are hundreds of chromosome aberrations in books at present. ?
In recent years, more and more attention has been paid to the role of genetic factors in the pathogenesis of tumors. Except for a few kinds of human tumors, almost all of them have chromosomal abnormalities, and different cancer cells have different chromosomal abnormalities. For example, abnormal pH chromosome is related to chronic myeloid leukemia; Meningioma is related to the deletion of chromosome 22; The abnormality of chromosome 14 is related to some lymphomas. Changes in human genetic material have led to changes in human characteristics. Judging from the harmfulness of genetic material changes, changes will inevitably destroy the original laws of the human body, and the consequences will be a mental blow to society and families, economic burden, and personal illness pressure. But from the point of view of evolution, variation provides rich materials for evolution. Gene mutation is of great significance to the emergence of new species. ?