How many different phenotypes and genotypes are obtained in Mendel’s F2 generation of dihybrid cross?
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Solution
Answer: 4 phenotypes and 9 genotypes.
Explanation:
In Mendel's dihybrid cross, two traits were considered. For a dihybrid cross for seed colour and seed type, he crossed two homozygous varieties, round yellow seeded plants (RRYY) with wrinkled green seeded plants (rryy).
It was followed by the selfing of F1 progeny which were round yellow seeded (RrYy).
The Punnett square here shows the different combinations of F2 progeny obtained.
The F2 progeny of Mendel’s dihybrid cross exhibit four different phenotypes: round yellow, round green, wrinkled yellow and wrinkled green.
There are 9 different genotypes:
RRYY, RRYy, RrYY, RrYy - 4 genotypes of the round yellow phenotype
RRyy, Rryy- 2 genotypes of the round green phenotype
rrYY, rrYy- 2 genotypes of the wrinkled yellow phenotype