Question

F${}_2$ generation in a Mendelian cross showed that genotypic ratio is 1: 2: 1. It represents a case of

• A. Co-dominance
• B. Dihybrid cross
• C. Monohybrid cross with complete dominance
• D. Incomplete dominance

Answer 1

Answer: (C)

Monohybrid cross with complete dominance

Monohybrid cross means considering a single trait for the cross over. For example, considering the length of a plant and the alleles are

Parents TT X tt

Gametes T T t t

F${}_1$ Tt Tt Tt Tt

Tt x Tt

F${}_2$ TT Tt Tt tt

so the offsprings are three tall but genotypically one homozygous tall and two heterozygous tall that represents complete dominance and one dwarf plant.

Hence the genotypic ratio of 1:2:1 represents the monohybrid complete dominance.

So, the correct answer is 'Monohybrid cross with complete dominance'