If we have that the color characteristic is regulated by the dominant gene R, by crossing two blue flowers with the recessive gene r, no violet flower will be obtained, since the rule of incomplete dominance describes that phenotypes can be obtained intermediates of homozygous parents, however in the case, we only have 2 parents with the same recessive conditions, which do not contribute to generate the violet, to produce one of the parents should have a gene that expresses the color red

6 0

2 years ago

Ability to roll the tongue is caused by a dominant allele. A woman is a "roller," but one of her parents is not. Reference: Ref

matrenka [14]

Answer:

1/2.

Explanation:

The autosomal dominant trait may en defined as the trait that can express itself even in the heterozygous condition and in the homozygous dominant condition as well.

Let the B allele is responisble for the roll tongue and b is recessive allele. The woman can roll the tongue and she must have the genotype Bb because her one parents is normal. The woman married with a man with non roller ( bb). The Bb × bb cross results in the following progeny Dd, Dd ( roller), dd and dd ( non roller). The probability of the child being a roller is 1/2,

Thus, the answer is 1/2.

5 0

2 years ago