*Linkage: Tendency of a gene present in a chromosomes to stay together in heredity transmission is linkage.

Factors affecting linkage:

1. Temperature and x-ray exposure decreases chances of linkage.
2.  Age increases the chances of linkage.

For example: In fruit fly, red eye & grey body occurs in some individual, Because genes holding the character of both lies in same chromosomes as linked gene.

*Recombination: During the Pachytene Stage of meiosis f, homologous chromosomes synapsed, which makes new combinations of genes, and these chromatids are called recombinants.

Factors affecting recominations:

1. X-ray exposure and temperature increases it.
2. Age decreases chances of recombination.

Difference Between Linkage and Recombinations:

Linkage keeps the gene within a chromosome and crossing over takes the gene away from it so, linkage induces the chances of variations but crossing over increases.