Describe what happens when inheritance of a particular trait follows a pattern of complete dominance?

Question

Describe what happens when inheritance of a particular trait follows a pattern of complete dominance?

Answer 1

In complete dominance there are only two types of phenotypes (the dominant and the recessive). For the dominant phenotype the genotype of the organism can be homozygous dominant or heterozygous. The recessive phenotype can only be manifested in the homozygous recessive condition.

For example the presence of dimples. We know that the presence of dimples is dominant over its absence hence we can denote its presence as D and its absence as b. Say woman with heterozygous(Dd) to the said trait marries another heterozygous then the cross would be:

Dd x Dd=1/2DD,1/2Dd,1/4dd

Therefore 3/4 of the children would have dimples and 1/4 won't. Notice that the only genotype possible for child without dimples is dd.

Hope this helps...