Gene mapping 

Gene mapping is the method to identify the locus of a gene and the distance between them.

A locus is the physical site or location of a specific type of gene on a chromosome.

• Q arm- long arm

• P arm- Short arm

• region

• sub-band

In the early 1900s two scientists called Sturtevant and Morgan made the first map of the gene in the fruit fly, Drosophila.

Offsprings almost always resemble one parent

If the gene is on the same chromosome then the trait is linked

whereas if the gene is present on different chromosomes then the trait is independently assorted.

Crossing over and recombination leads to a new trait