Analysis of genotypic variation

all humans have about the same genes but we don't have have same DNA sequence

because of mutations humans have different DNA sequences at different sites in their DNA

this has led to the development of the technique of

restriction fragment length polymorphism (RFLP)

consider the gene A with two alleles "A" and "a"

Alleles "A" and "a" are different forms of the same gene

they also differ in base sequence, as shown below

if the alleles are cut with a restriction enzyme the following fragments will be generated

these can be separated on an agarose gel to give the following pattern

this property is used