Download hwCh11_4 ONE GENE CROSSES Show work for full credit. Ans

1
BIO 208
NAME _______________________________________________
revised 2012
hwCh11_4 ONE GENE CROSSES
Show work for full credit. Answer on a separate piece of paper
1. Two black mice are mated. 16 of the progeny are black and 5 are brown
a. Diagram the cross
b. Show parental genotypes and phenotypes
c. Show progeny genotypes and phenotypes
d. What is the ratio of phenotypes in the offspring? (divide larger number by smaller to give a ratio.
For example 25 red and 4 pink is a ratio of 6.25:1)
2. In guinea pigs, rough coat is dominant over smooth coat. A rough coated guinea pig is bed to a smooth
one giving 8 rough and 7 smooth progeny in the F1 generation.
a. What are the genotypes and phenotypes of the parents?
b. Mate one F1 smooth animal back to its smooth parent. What phenotype(s) and in what ration of
progeny would you expect?
3. Yellow seeds is a dominant characteristic in pea plants. Pure breeding pea plants for yellow seeds were
crossed with pure breeding pea plants for green seeds. The F1 generation all exhibited yellow seeds. An
F1 plant was crossed to a green plant. Of 800 F2 plants, how many are expected to exhibit green seeds?
4. An autosomal recessive mutant allele causes the fruit fly, Drosophila, to exhibit a dark body. The
normal color is gray. Cross a dark-bodied female fly with a gray male fly whose father was dark-bodied.
What phenotypic ratio is expected in the offspring? Use these allele symbols: b allele = dark body
b+ allele = gray body.
5. Two phenotypically normal parents give birth to a child with sickle cell disease.
a. What is probability that their second child has sickle cell and is a girl?
b. What is the probability that 3rd child does not have disease and a boy?
6. What is the probability that two individuals with achondroplasia, a dominant disorder, in which DD is
fetal lethal (die before or shortly after birth), have child of normal height?
7. iGenetics 11.32
8. iGenetics 4.17 (read section on albinism)
9. iGenetics 4.20 (explain using Tay Sachs disease as the example).
10. iGenetics 4.28 (can list, do not need in essay format)
Try these but do not turn in: 4.4*, 4.6*, 11.1*,11.3*, 11.4*, 11.6*, 11.7 *, 11.10*, 12.31*, 12.33, 12.48*, 12.49*
*Answers in back of book