Estimation with Normal Gene Ratios
Linkage is manifested whenever two simultaneously assorting genes are found to be regularly associated. In the classic Mendelian experiment, two genes should assort at random in the testcross and in the intercross. However, in some crosses, completely random assortment is not realized. In each of the crosses, the four phenotypes can be represented as formed from the original and parental combinations or as recombinations. Formally, linkage is indicated whenever the expected number of parental phenotypes significantly exceeds the expected number of recombinant phenotypes. Two linkage phases can be defined, depending upon the nature of the initial cross. Two genes are said to be in coupling or repulsion phase, according to whether they were contributed by the same or different parents.
KeywordsDominant Gene Recessive Gene Complementary Gene Linkage Phase Epistatic Gene
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