REVIEW answers Genetics 1 (ch 14ish)
2 A couple who are both carriers for the gene for cystic fibrosis have two children who have cystic fibrosis. What is the probability that their next child will be phenotypically normal? 75%
4 In crossing a homozygous recessive with a heterozygote, what is the chance of getting a homozygous recessive phenotype in the F1 generation? 50
6 Black fur in mice (B) is dominant to brown fur (b). Short tails (T) is dominant to long tails (t). What proportion of the progeny of the cross BbTt x BBtt will have black fur and long tails? 8/16 \
8 What was the most significant conclusion that Gregor Mendel drew from his research? Traits are inherited in discrete units, one from each parent.
Use the information below to answer the following question(s).
A woman and her husband both show the normal phenotype for pigmentation, but both had one parent who was an albino. Albinism is an autosomal recessive trait.
10 What is the probability that their first child will be an albino? 25%
12 What is the chance that their fourth child will have a homozygous genotype? 50
14The advantage of chorionic villi sampling over amniocentesis is that CVS: can give results much earlier in the pregnancy than amniocentesis.
Use the information given below to answer the following question(s).
A woman who belongs to blood group A and is Rh positive has a daughter who is O positive and a son who is B negative. Rh positive is a simple dominant over Rh negative.
16 Which of the following is a possible genotype for the mother? IAiRr
18 Given the parents AABBCc x AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent 3/4
20 Two true-breeding stocks of garden peas are crossed. One parent had red, axial flowers, and the other had white, terminal flowers; all F1 individuals had red, axial flowers. If 1,000 F2 offspring resulted from the cross, how many of them would you expect to have red, terminal flowers? (Assume no linkage.)190
Refer to the terms shown below to answer the following question(s). Each term may be used once, more than once, or not at all.
1. incomplete dominance 2. multiple alleles 3. pleiotropy 4. epistasis 5. penetrance
22 One example is the ABO blood group system. 2
Use the following information to answer the question(s). Albinism (lack of skin pigmentation) is caused by a recessive autosomal allele. A man and woman, both normally pigmented, have an albino child together.
24 For this trait, what is the genotype of the albino child? homozygous recessive
26 The mother is now pregnant for a third time, and her doctor tells her she is carrying fraternal twins. What is the probability that both children will have normal pigmentation? 9/16
28 A 1:2:1 phenotypic ratio in the F2 generation of a monohybrid cross is a sign of intermediate inheritance
30 In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygous. When two roan cattle are crossed, the phenotypes of the progeny are found to be in the ratio of 1 red:2 roan:1 white. Which of the following crosses could produce the highest percentage of roan cattle? red x white
32 Three babies were recently mixed up in a hospital. After consideration of the data below, which of the following represents the correct baby/parent combinations?
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_ Couple # _ I _ II _ III _
_ Blood groups _ A and A _ A and B _ B and O _
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_ Baby # _ 1 _ 2 _ 3 _
_ Blood groups _ B _ O _ AB _
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(A) I-3, II-1, III-2 (B) I-1, II-3, III-2 (C) . I-2, II-3, III-1 (D) I-2, II-1, III-3 (E) I-3, II-2, III-1
(process of elimination...figure it out!)
34 What do all males inherit from their mother? mitochondrial DNA and X chromosome
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