Question

I did 1-5 but confused on the rest

LAB EXERCISE 4.1 continued Name 6 Remember that the ability to taste PTC is dominant to the inability. Two normally pigmented taster parents have an albino, taster son and a non-taster daughter with normal pigmentation. Using A and Tand a and t for the dominant and recessive alleles, respectively, create a Punnett square for two traits, as shown on pages 71-73 in the section "Transmission of Autosomal Traits: Two at a Time." a What are the genotypes of the parents? Mother Father b Explain how you figured out the parents' genotypes. c What do we know about the son's and daughter's genotypes based on their phenotypes? d Continuing to follow the steps outlined on pages 72-73, figure out which alleles are present in each parent's gametes for both albinism and PTC tasting Alleles in mother's egg cells: Alleles in father's sperm cells: e Set up a Punnett square for both traits (refer to Figs. 4.13 and 4.14), listing the mother's alleles across the top and the father's along the left side. Fill in the possible offspring f List the possible genotypes and phenotypes of the offspring, and the probability of each. Genotypes Phenotypes Probability 9 What is the chance of this couple's third child being a(n)? non-albino taster albino non-taster

Answer 1

6. T = WT dominant allele = Tasters
t = Mutant recessive allele = Non-tasters

A = WT dominant allele = Normal skin
a = Mutant recessive allele = Albino

Parents = Normally pigment and tasters
Progeny = Albino-taster son and Normal-nontaster daughter

Mother = TtAa
Father = TtAa

Both parents must be heterozygous for two genes.
This is due to the fact that the progeny exhibits both recessive phenotypes. So, they must carry a recessive allele.

Son = TTaa or Ttaa
Daughter = ttAA or ttAa

Gametes produced by mother = AT At aT at
Gametes produced by father = AT At aT at

Parental cross: AaTt X AaTt
Progeny:
9/16 = A_T_ = Normal tasters
3/16 = A_tt = Normal nontasters
3/16 = aaT_ = Albino tasters
1/16 = aatt = ALbino nontasters

See the image for the Punnet square

AT At ат at AT At AATT AATt Aatt AaTt AATt AAtt AaTt Aatt AaTT AaTt aalt aaTt AaTt Aatt aaTt aatt ат at