基因分离定律专讲（The law of gene segregation）.doc

基因分离定律专讲（The law of gene segregation） The law of gene segregation is devoted to sources: network resources, author: time: 2008-10-25, click: 282 I. the applicable range of the law of gene segregation 1. inheritance of sexual reproduction traits The essence of the law of gene segregation is the separation of alleles with the separation of homologous chromosomes, and the division of homologous chromosomes is a characteristic of meiosis that occurs in sexually reproducing cells by sexual reproduction 2. properties of eukaryotes 3. nuclear inheritance Only genes in eukaryotic cells change regularly with the regularity of chromosomes. The quantity of genetic material in cytoplasm is unstable and follows the rule of cytoplasmic maternal inheritance. The inheritance of 4. pairs of relative characters Two, the genetic problem of two or more relative characters, the law of separation can not be solved directly, indicating the limitation of the applicable range of segregation law. Two. The limiting factor of the law of gene segregation The laws of segregation of genes, F1 and F2, show the specific separation ratio and should have the following conditions: Each of the 1. pairs of relative characters was controlled by only one allele, and the alleles were completely dominant. 2., different types of female and male gametes can develop well, and the chances of fertilization are equal. 3. all offspring should be in a more consistent environment, and the survival rate is the same. 4. the experimental population should be large and the number of individuals should be large enough. Three, the gene separation law problem solving instruction 1. master the six most basic combinations of crosses DD * DD = DD; DD * DD = dd; DD * DD = Dd; Dd * DD = Dd = DD = 1: 1; Dd * Dd = (1DD, 2Dd) = 1DD = 3: 1; The Dd * Dd, DD: Dd = 1: 1 (Quan Xian) According to the separation of offspring than directly infer the genotypes of the parents and the performance type: If the segregation ratio of offspring i