Question

5. The ratio of genotype 1:2:1 in the offspring in F2 indicates that: (a) Both F1 parents are homozygous (by Both Fl parents are heterozygous (c) The Female F1 parent is homozygous and male Fl parent is heterozygous id The male Fl parent is homozygous and the female Fl parent is heterozygous​

Answer 1

Answer:

Mendel's explanation of the results of a dihybrid cross

Given the principles revealed in a monohybrid cross, Mendel hypothesized that the result of two characters segregating simultaneously (a dihybrid cross) would be the product of their independent occurrence. Consider two characters, seed color and seed shape. As previously shown, Y dominates y to determine seed color, and R factor for "round" dominates the r factor for "wrinkled" to determine seed shape. He then proceeded to test his hypothesis experimentally.

The P (Parental) cross is between true-breeding lines of wrinkled yellow peas (rrYY) and round green peas (RRyy). The F1 offspring are therefore all RrYy, and are all round and yellow. In forming the F2 plants, the alleles at the two loci segregate independently. That is, the chance of getting an R allele and a Y allele is 1/2 x 1/2, of getting an R and a y 1/2 x 1/2, and so on. Thus, all four possible diallelic combinations occur with an equal probability of 1/4. The same is true for both parents. Given four possible gamete types in each parent, there are 4 x 4 = 16 possible F2 combinations, and the probability of any particular dihybrid type is 1/4 x 1/4 = 1/16. The phenotypes and phenotypic ratios of these 16 genotype can be determined by inspection of the diagram above, called a Punnet Square after the geneticist who first used it.

Answer 2

Answer:

both F1 parents are heterozygous

Explanation: