Essays on Test Cross

Patterns of Inheritance

A homozygous brown mink was crossed with a silverblue mink. Brown (B) is dominant to silverblue. There were 9 offspring. What color were they? (B) Two of the offspring were mated. What would the ratio of brown to silverblue offspring be? What fraction of the offspring will be homozygous brown? Heterozygous? Homozygous recessive?

Let B represent the allele for brown color and b represent the allele for silver blue

Punnet square between homozygous brown mink and silver mink homozygous brown mink X Silver mink bb X BB

All the 9 offspring were brown

Mating two of the offspring Punnet square showing f1 generation will be as follows Bb X Bb Ratio of brown to silverblue is 3: 1 Fraction of homozygous ...

Answer for Part 1

A: In the F1 generation there were 445 purple and 437 white flowers. If the homozygous dominant genotype is (PP) and heterozygous genotype is (Pp); then the recessive genotype would be (pp).

White flowers = (pp) = 437 The ratio of purple flowers to white flowers is nearly 1:1, i.e. the number of purple flowers to the number of white flowers is nearly same. Hence, the parents would heterozygous purple flower (Pp) with homozygous recessive (pp). The following is an example of a test cross. B: In genetics, a test cross, first introduced by Gregor Mendel, is used to determine if a ...

Test cross

What was the phenotypic ratio for the offspring resulting from this testcross? Results for the F1 generation for monohybrid cross between a female fly with brown eye (BW) color with a male fly having ebony body (E) color are as shown below.

Fly lab Lab Notes for Steven F

Parents (Female: BW) x (Male: E) Offspring Phenotype Number Proportion Ratio Female: + 494 0.5067 1.027 Male: + 481 0.4933 1.000

Total 975

All the offspring had a wild-type phenotype for the brown eyes and ebony body. This shows that, both brown eye and ebony body are recessive genes. The phenotypic ratio for the offspring resulting from the ...