In a pea plant seed color is determined by two alleles: Y (Yellow, dominant) and y (green, recessive). Which parental cross would most likely result in offspring showing a 1:1 ratio of yellow to green seeds?
- A. Yy x YY
- B. Yy x yy
- C. Yy x Yy
- D. YY x yy
Explanation
Crossing a heterozygote with a homozygous recessive gives half Yy and half yy, that is one yellow to one green, which is the classic test cross. Yy by Yy gives three yellow to one green, and any cross involving YY gives all yellow because every offspring receives at least one dominant allele. Recognising the test cross by its 1:1 outcome is the quickest route.
Related questions
The separation of the two alleles of a gene so that each gamete receives only one of them is Mendel's law of
The F2 phenotypic ratio of a dihybrid cross between two heterozygotes is
To find out whether a tall pea plant is homozygous or heterozygous, it should be crossed with
The genotypic ratio of the F2 generation of a monohybrid cross is
A red flowered four o'clock plant crossed with a white flowered one gives pink flowered offspring. This is an example of