at the second locus (genotype rr P_). If two recessive alleles are present at the first and at the second loci (rr pp), a single comb is produced. Progeny with what types of combs and in what proportions will result from the following crosses? a. RR PP x rr pp d. Rr pp × Rr pp b. Rr Pp xrr PP e. Rr pp xrr Pp c. Rr Pp x Rr Pp f. Rr pp xrr pp *25. In chickens, comb shape is determined by alleles at two loci (R, r and P, p). A walnut comb is produced when at least one dominant allele R is present at one locus and at least one dominant allele P is present at a second locus (genotype R_P_). A rose comb is produced when at least one dominant allele is present at the first locus and two recessive alleles are present at the second locus (genotype R_pp). A pea comb is produced when two recessive alleles are present at the first locus and at least one dominant allele is present

2) In chickens, feather colour is determined by alleles at 2 loci. Chickens with the allele I have white feathers, whatever alleles they have at the other locus. Chickens with the genotype cc also have white feathers, although presence of the dominant allele C results in coloured feathers, so long as the I allele is absent. Write down all the possible genotypes that produce a) white chickens b) coloured chickens c) which is the epistatic gene? d) what type of epistasis is this?

In individuals affected by cystic fibrosis, salt crystals may appear afterperspiration dries up. In addition, the disease causes respiratory disorderswhich can be both debilitating and lethal. It occurs in individuals homozygousfor recessive gene. If 2 normal parents had a daughter with the symptoms ofthis disease, and a normal son, what is the probability that he might be acarrier of the recessive gene?Express answer in fraction form.

is it possible to determine to genotype if an individual expressing a dominant phenotype

In domestic chicken, feather colour and shape are two traits which are controlled by autosomal alleles that are co-dominant. Table 2 shows the alleles and phenotype of both traits. The heterozygous state for feather colour is grey while the heterozygous state for feather shape is mildly frizzled. TABLE 2 Trait Feather colour Allele CB CW SS SF Effect Produces black feathers in homozygotes Produces white feathers in homozygotes Produces straight feathers in homozygotes Produces frizzled feathers in homozygotes Feather shape A farmer bred a black frizzled rooster with a grey mildly frizzled hen. Draw a genetic diagram to show the expected results of this cross. Include in your answer the phenotypic ratios. Is it necessary to do a test cross to determine the genotypes of the offspring? Explain your answer. The farmer would like all his chickens grey and mildly frizzled. What would you advise him to do? Explain your answer.

CAay Bew Scace In guinea pigs, rough coat is daminant (R) to smooth coat () and black coat (B) is dominant to white coat (b). A rough black guinea pig bred with a rough white one produces 29 rough black offspring, 31 rough white offspring, 11 smooth black and9 smooth white. Give the genotypes of the parents, the probability for the offspring, and the actual number of each kind of offspring you would expect. 9. Genatype of the rough, black parent? Genatype of the rough, white parent? Genotypes Phenotypes What is the probability of getting rxigh, black offspring? What is the probability of getting ough, white offspring? What is the probability of getting smooth, black offspring? What is the probability of getting smooth, white offspring? Of the 80 offspring that were produced, we might have expected how many of them to be rough and black? Of the B0 offspring that were produced, we might have expected how many of them to be rough and white? Of the 80 offspring that were produced, we might…

Date Name Punnett Square Practice Worksheet 1) For each of the genotypes (AA, Aa or aa) below determine what the phenotype would be. Purple flowers are dominant to white flowers. PP Pp PP Hairy knuckies are dominant to non-hairy knuckles in humans. Hh hh HH Bobtails in cats are recessive. Normal tails are dominant. Tt tt TT 2) For each of the following write whether it is homozygous dominant, heterozygous or homozygous recessive. AA gg Pp Ii TT Use the following information for questions 3-5: In dogs, the gene for fur color has two alleles. The dominant allele (F) codes for grey fur and the recessive allele (f) codes for black fur. 3) The female dog is heterozygous. The male dog is homozygous recessive. Figure out the percentage or ratio of possible phenotypes and genotypes of their puppies by using a Punnett Square. Plae the oileles for the mule parent helm One alele n e h lie: % of possible Genotypes: FF Plar the alfele f he emle p r ti side One elleir on ch tine Ff: % of possible…

Albino rabbits (lacking pigment) are homozygous forthe recessive c allele (C allows pigment formation).Rabbits homozygous for the recessive b allele makebrown pigment, while those with at least one copy ofB make black pigment. True-breeding brown rabbitswere crossed to albinos, which were also BB. F1 rabbits, which were all black, were crossed to the doublerecessive (bb cc). The progeny obtained were 34black, 66 brown, and 100 albino.a. What phenotypic proportions would have beenexpected if the b and c loci were unlinked?b. How far apart are the two loci?

. In mice, the dominant allele Gs of the X-linked geneGreasy produces shiny fur, while the recessive wildtype Gs+ allele determines normal fur. The dominantallele Bhd of the X-linked Broadhead gene causesskeletal abnormalities including broad heads andsnouts, while the recessive wild-type Bhd+ alleleyields normal skeletons. Female mice heterozygousfor the two alleles of both genes were mated withwild-type males. Among 100 male progeny of thiscross, 49 had shiny fur, 48 had skeletal abnormalities,2 had shiny fur and skeletal abnormalities, and 1 waswild type.a. Diagram the cross described and calculate thedistance between the two genes.b. What would have been the results if you hadcounted 100 female progeny of the cross?

In a certain breed of dog, the dominant, B, is required for black fur; it’s recessive, b, produces brown fur. However, the dominant, I is the epistatic to the color locus and can inhibit pigment formation. The recessive allele, i, on the other hand, permits pigment deposition in the fur. What would be the phenotypes of the following sets of parents and what would be the results of the mating BBii x bbIi     1/4 black, 1/4 brown, 1/2 no color     1/2 black, 1/2 brown     1/2 black, 1/2 no color     1/3 black, 1/3 no color, 1/3 brown