In guinea pigs, short hair (L) is dominant to long hair (I), and the heterozygous condition of yellow coat (C') and white coat (CW) give cream coat. A short-haired, cream guinea pig is bred to a long-haired, white guinea pig, and a long-haired, cream baby guinea pig is produced. When the baby grows up, it is bred back to the short-haired cream parent. Use a Punnet square to diagram the cross between the long-haired, cream baby guinea pig and the short-haired 4. a. cream parent. b. Give the genotypic and phenotypic ratios of the expected offspring of the cross in (a).

A recessive epistasis cross gives in the F2 a 9:3:4 phenotypic ratio. What is the expected phenotypic ratio when the F1 (BbEe) is crossed with the double recessive homozygote (bbee)? Keeping in mind ee masks the expression of B.

n mice, the Ay allele of the agouti gene is recessive lethal, but it is dominant to wild type for yellow coat color. For an unlinked gene called C, cc makes no pigment and are albino while C_ mice will make pigment in in their coat. cc is epistatic to A or AY with regard to coat color, but not for viability. What phenotypic ratio would you expect from the progeny produced by two mice of the genotype: AAy Cc? (Note that “agouti” is the wild-type coat color.)     9 agouti : 3 black : 3 white : 1 yellow     3 agouti : 6 yellow : 3 white     12 yellow : 3 black: 1 brown     9 agouti : 3 yellow : 4 white       8 yellow : 3 black: 1 brown

. The normal eye color of Drosophila is red, but strains inwhich all flies have brown eyes are available. Similarly,wings are normally long, but there are strains with shortwings. A female from a pure line with brown eyes andshort wings is crossed with a male from a normal pureline. The F1 consists of normal females and short-wingedmales. An F2 is then produced by intercrossing the F1.Both sexes of F2 flies show phenotypes as follows:38 red eyes, long wings38 red eyes, short wings18 brown eyes, long wings18 brown eyes, short wingsDeduce the inheritance of these phenotypes; useclearly defined genetic symbols of your own invention.State the genotypes of all three generations and thegenotypic proportions of the F1 and F2.Unpacking Problem 31Before attempting a solution to this problem, try answering thefollowing questions:1. What does the word normal mean in this problem?2. The words line and strain are used in this problem.What do they mean, and are they interchangeable?3. Draw a simple…

astigmatism and non-red hair are produced by a different pair of completely dominant genes. Hence, astigmatic persons whose hair is not red are A-B- How often in families of four children where the parents are both heterozygous for astigmatism and heterozygous Tor non for non red hair would you expet 2 astigmatic red haired girls and 2 pon astigmatic brown haired boys? ANSWER

Pigment in the mouse is produced only when the C allele is present.Individuals of the cc genotype have no color. If color is present,it may be determined by the A and a alleles. AA or Aa resultsin agouti color, whereas aa results in black coats.(a) What F1 and F2 genotypic and phenotypic ratios areobtained from a cross between AACC and aacc mice?(b) In the three crosses shown here between agouti femaleswhose genotypes were unknown and males of the aaccgenotype, what are the genotypes of the female parents foreach of the following phenotypic ratios? (1) 8 agouti         (2) 9 agouti               (3) 4 agouti8 colorless             10 black                      5 black                                                                  10 colorless

Miniature wings in Drosophila result from an X-linked allele (Xm) that is recessive to the allele for long wings (X+). Sepia eyes are produced by an autosomal allele (s) that is recessive to an allele for red eyes (s+). Q. A female fly that has miniature wings and sepia eyes is crossed with a male that has normal wings and is homozygous for red eyes. The F1 flies are intercrossed to produce the F2. Give the phenotypes, as well as their expected proportions, of the F1 and F2 flies.

A true-breeding rabbit with agouti (mottled, grayish brown) fur crossed with a true-breeding rabbit with chinchilla (silver) fur produces all agouti offspring. A true-breeding chinchilla rabbit crossed with a true-breeding Himalayan rabbit (white fur with pigmented nose, ears, tail, and legs) produces all chinchilla offspring. A true-breeding Himalayan rabbit crossed with a true-breeding albino rabbit produces all Himalayan offspring. Explain the inheritance of the fur colors.

The ABO blood groups in humans are expressed as the IA,IB and i alleles. The IAallele encodes the A blood group antigen, IB encodes B, and i encodes O. Both A and B are dominant to 0. If a heterozygous blood type A parent (IAi) and a heterozygous blood type B parent (IBi) mate, one quarter of their offspring are expected to have the AB blood type IAIBin which both arnigens are expressed equally. Therefore, ABO blood groups are an example of: a. multiple alleles and incomplete dominance b. codominance and incomplete dominance c. incomplete dominance only d. multiple alleles and codominance

In Section 12.3, ''Laws of Inheritance," an example of epistasis was given for the summer squash. Cross white WAvYy heterozygotes to prove the phenotypic ratio of 12 white:3 yellow:l green that was given in the text.