染色体（Chromosome）.docVIP

染色体（Chromosome） Edit this paragraph introduction Dye the cells that are dividing with alkaline dyes, and you will find that there are many dark colored substances in the nucleus called chromosomes (Chromosome). In the nucleus of a cell, there is a substance that is easily colored with an alkaline dye, called chromatin. Chromosomes are just another form of chromatin. Their composition is the same, but because of the configuration is not the same, so there are still some differences. Chromosomes are formed by the formation of chromatin at the mitotic interval of cells. The chromatin of prokaryotic cells used for chemical analysis contains naked DNA, i.e., not associated with other classes of molecules. The eukaryotic chromosomes are more complicated, consisting of four elements: DNA, RNA, group protein (lysine rich low molecular weight alkaline protein, acid and arginine ammonia in at least five different types) and non histone (acid). The ratio of DNA to histone is close to 1:1. The number of chromosomes in normal human somatic cells is 23 pairs, and has definite morphology and structure. Abnormalities in morphology, structure, or quantity of chromosomes are called chromosomal abnormalities, and diseases caused by chromosomal abnormalities are chromosomal diseases. Chromosomal diseases have been found in more than 100 kinds of chromosome disease often can cause miscarriage, Down syndrome, congenital multiple malformations, and cancer in clinic. The incidence of chromosomal abnormalities is not uncommon in the chromosomes of the average new person As many as 0.5%~0.7% in the offspring population, such as the average number of births per 3000 births per year in our hospital, among which there may be 15~20 cases with chromosomal abnormalities. In early spontaneous abortions, approximately 50%~60% was caused by chromosomal abnormalities. The common causes of chromosomal abnormalities are ionizing radiation, chemical exposure, microbial infection, and heredity. Clinically