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In pea plants, yellow seeds are dominant to green. If a heterozygous yellow seeded plant is crossed with a green seeded plant, what ratio of yellow and green seeded plants would you expect in F1 generation?
A
9 : 1
B
1 : 3
C
3 : 1
D
50 : 50
Detailed Solution
Let G be the allele for yellow seeds (dominant) and g the allele for green seeds (recessive).
Heterozygous yellow seeded plant: Gg. Green seeded plant: gg (homozygous recessive).
The cross is Gg x gg, which is a test cross.
Gametes of the heterozygous parent: G and g in equal numbers. Gametes of the green parent: all g.
Offspring: Gg (yellow) and gg (green) in equal numbers.
So the ratio of yellow to green seeded plants is 1 : 1, i.e. 50 : 50.
Heterozygous yellow seeded plant: Gg. Green seeded plant: gg (homozygous recessive).
The cross is Gg x gg, which is a test cross.
Gametes of the heterozygous parent: G and g in equal numbers. Gametes of the green parent: all g.
Offspring: Gg (yellow) and gg (green) in equal numbers.
So the ratio of yellow to green seeded plants is 1 : 1, i.e. 50 : 50.