Answer:
There is no punnet square attached but generally none of the offsprings from this cross will be homozygous dominant. The answer is 0.
Explanation:
The question illustrates a single trait encoded by a single gene. According to Mendel, a gene comes in two alternative forms called ALLELES. Each allele encodes different characters of the same gene. For example, let's use the trait for height encoded by a certain gene that has alleles T for tallness and t for shortness. T is dominant over t, meaning that T (tallness) will always mask the phenotypic expression of t (shortness) in a heterozygous state.
A heterozygous parent contains different alleles of the same gene i.e. Tt in this case. However, due to the dominance of allele T (tallness) over allele t (shortness), the tall trait will be expressed. On the other hand, a homozygous recessive parent contains the same alleles for the recessive trait i.e. tt
Using a punnet square, a cross between a heterozygous (Tt) parent and a homozygous recessive parent (tt) will produce offsprings with genotypes: Tt and tt in a 1:1 proportion.
Tt is heterozygous dominant
tt is homozygous recessive
None of the offsprings are homozygous dominant (TT), hence, the probability of producing a homozygous dominant offspring is 0.
t t
T Tt Tt
t tt tt
