Is there any difference in the nucleotide sequence of dominant and recessive alleles?
The nucleotide sequence of the two alleles is functionally different, which is why they produce two different polypeptides. Whereas the recessive allele may produce an ineffective polypeptide or no polypeptide at all, the domimant allele does. Consider a flower petal. The “recessive” allele does not produce a chromogenic polypeptide, so the petals remain white. However, the “dominant” allele produces a polypeptide that causes the petals to appear red. Therefore, the petals will be as long as there is a “dominant” allele present. This is the basic difference between recessive and dominant alleles- the polypeptides they produce.
