Biology

Mendelian Monohybrid Cross

Represent a heterozygous monohybrid cross.

Tt × Tt → Genotype Ratio 1:2:1

Formula Explanation

Under simple Mendelian inheritance, crossing two heterozygotes produces genotype proportions of one homozygous dominant, two heterozygous and one homozygous recessive.

Variables Explained

T = Dominant allele; t = Recessive allele.

Solved Example

What is the genotype ratio of Tt × Tt?
TT:Tt:tt = 1:2:1.

Exam Tip

The phenotype ratio is 3:1 only under complete dominance and the usual Mendelian assumptions.