An organism is homozygous dominant for one trait and heterozygous for another. What is the probability of the organism producing a gamete with one dominant allele and one recessive allele for these traits?

A. 4 out of 4

B. 1 out of 4

C. 1 out of 2

D. 2 out of 16

The answer is C

It is easiest to envision why if you imagine the alleles in a 2x2 grid. The homozygous alleles outside the grid along the top, (BB), and the heterozygous ones along the left hand side, (Bb). If you take each allele to the two boxes aligned with it in the grid, you will be left with two BB combinations and two Bb combinations. This is a probability of 2 out of four or 1 out of 2 on the gamete produced being heterozygous.

C. 1 out of 2

Explanation:

The probability of the organism producing a gamete with one dominant allele and one recessive allele for these trait is 2 out of 4 which can be further reduced to 1 out of 2.

For a cross between Homozygous and heterozygous individual we will get 2 homozygous and 2 hetrerozygous individual. The heterozygous individual has one homozygous allele and one heterozygous allele