Answer: Mutation. The allelic variations that make evolution possible are generated by the process of mutation, but new mutations change gene frequencies very slowly, because mutation rates are low. Assume that the gene allele A1 mutates to allele A2 at a rate m per generation and that at a given time the frequency of A1 is p.
Type 2 causes serious medical problems beginning in infancy, while Type 3 progresses more slowly than Type 2. There are also other more unusual forms that are hard to categorize within the three Types. Gaucher disease is caused by changes (mutations) in a single gene called GBA. Mutations in the GBA gene
If the plant has two dominant alleles for stem height (TT) then it is tall. If the plant has two recessive alleles for stem height (tt), it is short. If the plant is a hybrid (Tt), it is tall.
