Some guy from the 20th century
Answer:
Phenotype ratio= 12 colorless : 3 purple : 1 red
Genotype ratio= 1:2:1:2:4:2:1:2:1
Explanation:
According to the given information, the dominant allele "I" is epistatic to P and p alleles and presence of "I" inhibits the expression of both "P" and "p" alleles.
A cross between two heterozygous plants for both locus would give the F2 progeny in 12 colorless: 3 purple: 1 red ratio.
Here, the F2 genotype with "I-G" and "I-gg" would produce colorless kernels while the ones with "ii-G-" would exhibit purple colored kernels. The F2 genotype "iigg" would beak red kernels.
Hence, the phenotype ratio= 12 colorless : 3 purple : 1 red
Genotype ratio would be same as for the mendelian dihybrid cross= 1 IIPP: 2 IIPp :1 IIpp: 2 IiPP :4 IiPp: 2 Iipp: 1 iiPP :2 iiPp: 1 iipp
<span>Additional facts:
A test cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait so the unknown genotype can be determined from that of the offspring.
Answer:
You'd use it when you wish to see if the one that you think is a homozygous dominant is a purebred, because if you did get a recessive offspring then it proves that the animal is a heterozygous and not a purebred.</span>