Linkage and Crossing over. Lecture 5 Dr. Attya Bhatti. Linkage. Linkage is defined genetically as the failure of two genes to assort independently. Linkage occurs when two genes are close to each other on the same chromosome.
Table: Sweet Pea Phenotypes Observed in the F2 by Bateson and Punnett.
(43 + 22) ÷ 14513 = 1.4 percent.
The two genes T and U are farther apart on a chromosome than V and W. Chromatids cross over between T and U in a larger proportion of meioses than between V and W, so the recombinant frequency for T and U is higher than that for V and W.
The place on the map and on the chromosome where a gene is located is called the gene locus (plural, loci).