Consider the genetic cross for absent-mindedness, which is a dominant trait. All of the offspring from this cross will be absent-minded. If two parents that are absent-minded have offspring that are not, what MUST be the genotypes of the parents?
1 Answer
Oct 25, 2017
Both parents must heterozygous having one dominate gene for absent mindedness and one gene that codes for normal brain function.
Explanation:
In a punnett square cross for one trait there are four possibilities
AA, Aa, aA aa
Where A stands for the dominate gene for absent mindedness
Where a stands for the recessive gene for normal brain function
AA, Aa, aA all result in an offspring that is absent minded.
aa results is an offspring with normal brain function.
A a
A AA Aa
a aA aa
If one parent was homozogous for the trait all of the offspring would be absent mindedness
A A
A AA AA
a a A aA
