State Coupling and Repulsion theory.

How crossing over differs from linkage?

How and where chiasma is formed?

What is recombination? Which is the widely accepted model of DNA recombination ?

Given below is a sequence of alphabets representing the genes of chromosome. Observe it and answer the questions.
A- B - C - D - E - F - G - H - I - J -K.
(a) Write the sequence of genes after the chromosome undergoes terminal deletion of single gene.
(b) What will be the gene sequence, if the genes E and F undergoes tandem duplication?
(c) Consider the centromere is located between the genes F and G and write a gene sequence, after paracentric inversion occurs in between the genes C, D and E.