Answer:
The smallest number of copies of the dominant allele for polydactyly that could be found in a body cell of a person is one, since polydactyly is caused by an autosomal dominant allele.
Two copies of the recessive cystic fibrosis (CF) allele are there in a body cell of a person suffering from CF, as it is inherited in an autosomal recessive manner.
Explanation:
Polydactyly is a condition in which the individual has extra fingers or toes. It is an autosomal dominant condition caused by a dominant allele of the faulty gene. So to inherit the polydactyl condition, the offspring need to carry just one dominant allele from their parents.
If the dominant allele can be shown as P and the recessive allele can be shown as p ,then the offspring who is homozygous (PP) or heterozygous (Pp) for the dominant allele will develop Polydactyly.
Cystic fibrosis is a genetic disease inherited in an autosomal recessive manner, which is caused by a faulty recessive allele on chromosome 7. This disorder is characterized by the buildup of thick, sticky mucus in the cell membranes of the body's organs and cause progressive damage, mainly to the respiratory system and digestive system. To inherit cystic fibrosis, the offspring has to carry two copies of the faulty gene, one from each of the parents.
If the recessive allele can be shown as 'f
'and the dominant allele can be shown as 'F
', then only the person who is homozygous 'ff' with the recessive allele will develop cystic fibrosis. The person who is homozygous with the dominant allele 'FF' will not develop cystic fibrosis (need two faulty alleles (ff) for the condition) and the person who is heterozygous 'Ff' will be a carrier of the disease, but will not develop cystic fibrosis and have no symptoms.
