Genetics & Evolution Principles Of Inheritance & Variation

• 2019: A tall pea plant (Tt) is crossed with a dwarf pea plant (tt). The ratio of tall plants to dwarf plants in the progeny would be
  • 1 : 1
  • 3 : 1
  • 1 : 2
  • 9 : 7

The answer is 3 : 1.

This is because the tall allele (T) is dominant to the dwarf allele (t). In a cross between a tall plant (Tt) and a dwarf plant (tt), half of the offspring will be tall (Tt) and half will be dwarf (tt).

A cross between two pea plants, one having round green seeds and the other having wrinkled yellow seeds, produced offspring with round green seeds in the ratio of 9 : 3 : 3 : 1. This is because * the two genes are linked

• the two genes are dominant traits
  • the two genes are recessive
• the two genes are codominant in expression

The answer is that the two genes are dominant.

This is because the round seed allele (R) and the wrinkled seed allele (r)