Genetics null alleles

[tigerface07]

Consider one gene and its alleles. Describe the null allele mutation which leads to incomplete dominance. Describe the null allele mutation which leads to the allele being dominant over the normal allele. The description should include what happens to the DNA of the gene, the mRNA transcript, protein, and protein function. For both cases, what happens when monohybrid F1s are selfed? What are the resulting genotypes and their ratios? What are the resulting phenotypes and their ratios?

[JackBean]

here you have, what is null allele
http://en.wikipedia.org/wiki/Null_allele
now you should be able to describe what happens with DNA, mRNA or protein.