What Is the Connection Between Blood Type and Paternity?
The broad blood type refers to the antigen types of red blood cells, white blood cells, platelets, and various plasma proteins in the blood of higher animals and humans. The narrow blood type refers only to the type of red blood cell antigen, which is a commonly used blood type definition. In 1924, the German scholar F. Bernstein proved that the ABO blood group was controlled by three multiple alleles, and initiated the research of blood group genetics. Blood group inheritance is the theoretical basis for clinical blood transfusion and organ transplant matching. Blood type, as a hereditary trait, is rarely affected by the environment, so it is an excellent genetic marker that can be used for paternity testing, disease association analysis, and ethnic evolution studies.
Blood group inheritance
- ABO blood group system
- 1900 1902 Austrian medical scientist K. Landsteiner and other applied red
- Generally the blood type is unchanged for life. Human blood types are usually divided into A, B, O and AB. Blood group inheritance is by means of chromosomes in cells. There are 23 pairs of chromosomes in human cells. Each pair consists of two single chromosomes, one from the father and the other from the mother. The main component of a chromosome is DNA, which is the DNA that determines hereditary traits and functions. DNA can be divided into many segments, each of which has a specific genetic trait and function. These segments are called genes. A small piece of DNA at the same position on two single chromosomes in a pair of chromosomes is called an allele.
- The genetic locus of the ABO blood group system is on the 9th pair of chromosomes. The human ABO blood type is controlled by three genes A, B, and O, but there are only two ABO system genes on the ninth pair of chromosomes in each human cell, that is, AO, AA, BO, BB, AB, OO A pair of alleles, of which A and B genes are dominant genes and O gene is recessive gene.
- Erythrocyte blood group antigens are a class of glycoproteins; antigen specificity is determined by the glycosyl structure of the glycoprotein. blood group
- Simian erythrocytes have ABO antigens, corresponding antibodies in serum, and substances A, B, and H in saliva. Baboons and most monkeys do not have ABO antigens, but there are substances A, B, and H in saliva. Apes, baboons and monkeys have Lewis in their saliva. These facts indicate that the ABO antigen in saliva appeared first and the ABO antigen on red blood cells appeared later in the evolution process.
- Simian red blood cells have the MN blood type. Guinea pig anti-rhesus erythrocyte sera can be used to detect a human LW antigen associated with Rh antigen. The red blood cells of apes, baboons, and many monkeys have the LW antigen. Monkeys do not have Rh antigens, but all apes have certain forms of D and C antigens. E / e series antigens are only found in humans. This in turn indicates that the LW gene is older than the Rh gene in evolution; various Rh genes also gradually emerged during the evolution process.
- Among the various apes, dogs, and mice, only the gibbon has the Xg2 antigen, and it appears to be X-linked. The relationship between gibbon and human is not as close as that of other apes, but they share the Xg2 antigen with humans, which is difficult to understand at present.
- Transfusion and transplant matching
- In clinical blood transfusion, if the recipient's blood contains antibodies against the donor's red blood cell antigen, it often results in a severe hemolytic transfusion reaction. The transfused blood does not interfere if it contains antibodies against the recipient's red blood cell antigen. This is because the input antibody is immediately diluted by the blood of the recipient and is absorbed by the tissue cells. Therefore, the principle of blood transfusion matching is that the imported red blood cells cannot have the antigen lacking in the recipient.
- When selecting donors and recipients in clinical organ transplantation, the red blood cell type must be matched, and its principle is exactly the same as the blood transfusion type. The ABO blood type must be matched, and the effects of Rh and P blood types on graft survival are inconclusive. In the case of recipients using immunosuppressants, no other blood group system was affected.
- Neonatal hemolysis
- This is the result of a mismatch between the fetus and the mother's red blood cell blood group. Unmatched blood types can cause
- chromosome
- A slightly stick-shaped, darkly colored body located in the nucleus of a cell that is recognized only when the cell divides. It is made up of many genes arranged in a line.
- gene
- It is a piece of DNA located on the chromosome. It is the basic unit of inheritance. It can express specific functions, determine specific traits and variations of these traits.
- Dominant and recessive genes
- Used to indicate offspring traits. When two relative parents are combined, they are called dominant genes, otherwise they are called recessive genes. For example, after a yellow-blowing plant and a white-blooming plant are crossed, if the offspring bloom is still yellow, then the yellow-blooded offspring is dominant and the white-blooded offspring is recessive.
- Homozygotes and heterozygotes
- At the corresponding sites of a pair of chromosomes, the same allele is called homozygote; otherwise, it is called heterozygote.
- Phenotype and heredity
- The latter type that can be detected with antiserum is called a phenotype: otherwise, it is called a hereditary type.
- Alleles and multiple alleles
- One of two or more genes, which determines the two opposite traits in heredity, is located at the same site on the homologous chromosome. They are called alleles. Conversely, when there are more than two genes in one gene locus at the same locus of a homologous chromosome, they are called complex alleles.
- Homologous chromosome
- In diploid cells, chromosomes exist in pairs, one from the father and one from the mother, with the same morphology and size, and paired with each other before the meiosis. Contains similar genetic information.
- In the second generation, humans can obtain certain characteristics of the previous generation. This phenomenon is called heredity. Human blood type is
- Somatic chromosomes are called homozygotes if the alleles from both parents are the same (eg, alleles A and A on some type A chromosomes): if the genes contained are not the same, they are called heterozygotes For example, the alleles on type A human chromosomes of A are A and O). In other words, each individual has two and only two alleles at a certain locus, and each allele is from each parent. If the genes from both parents are the same, the individual is called a homozygote, if not, it is called a heterozygote. The sum of genes on a pair of chromosomes, whether homozygous or heterozygous, is called the genetic form. As mentioned above, the genetic formulas of the two people are AA and AO. However, not all the inherited genes are expressed, and the traits that can be expressed are called expressions. If the inheritance is AA and AO, the expression is A, which is what we usually call A type. Visible blood type actually refers to its manifestation. The blood type's expression and heredity are different because some genes, whether homozygous or heterozygous, can control the traits they can express. Such genes are called dominant genes. It is expressed only when homozygous, but not when heterozygous. This gene is called a recessive gene. In the ABO blood group system, the A and B genes are dominant genes, and the O gene is a recessive gene. For example, in a pair of chromosomes, one chromosome carries the A gene and the other carries the O gene. The genetic form of the person is AO, but the expression is A, that is, type A, not type O. O-type human body This is the O gene on the two chromosomes.
- Based on this reasoning, the genetic form and performance of the ABO blood group system are as follows:
- Table 1: ABO blood types and their corresponding genetic formulas
- Blood type or phenotype genetic or genotype
- A AA, AO
- B BB, BO
- O OO
- AB AB
- That is, expressions A, B, O, and AB; genetic formulas AA, AO, BB, BO, OO, and AB.
- ABO blood group identification, usually only two anti-sera, anti-A and anti-B serum, can be divided into four blood groups.
- According to the genetic law of blood type and the clinical working example, the blood type of children born between spouses is shown in Table 2.
- Table 2: Blood types of children born to various ABO spouses:
- Blood types that match-matched children may have
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