How does the location of 2 genes impact their expression

The location of the two genes may lead to linkage of the genes.

Explanation:

Linkage is the phenomenon which measures the relationship between the distance of the genes on a chromosome and its rate of segregation during gametogenesis. During meiosis there's an event called crossing over. This crossing over leads to the independent segregation of the genes that aren't present on same chromosome.

But when the noted genes are present on same chromosomes, the crossing over may or may not take place between them. So they may get into one gamete as a group. This will change the probability and Mendel's law of independent segregation.