Gene Review Questions

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ANSWERS TO REVIEW QUESTIONS CHAPTER 5 1. a. Lethal alleles eliminate a progeny class that Mendel's laws predict should exist. b. Multiple alleles create the possibility of more than two phenotypic classes. c. Incomplete dominance introduces a third phenotype for a gene with two alleles. d. Codominance introduces a third phenotype for a gene with two alleles. e. Epistasis eliminates a progeny class when a gene masks another's expression. f. Incomplete penetrance produces a phenotype that does not reveal the genotype. g. Variable expressivity can make the same genotype appear to different degrees. h. Pleiotropy can make the same genotype appear as more than one phenotype because subsets of effects are expressed.…show more content…
24 linkage groups, 22 pairs of autosomes, and the X and the Y 13. Markers may be variable restriction sites, variable short repeated sequences, or single nucleotide polymorphisms (SNPs). 14. Linkage: inherited together as on the same chromosome. Marker: a gene or DNA sequence with a known location that can be used to localize a gene of interest with an unknown location. ANSWERS TO APPLIED QUESTIONS 1. a. D b. C. c. A d. H e. G f. C g. H h. F i. G 2. Haplotypes can reveal if people without symptoms have the haplotype associated with the condition. These people are non-penetrant. If the genotype is lethal, individuals with the haplotype containing the lethal allele should not exist. 3. a. 1/2 b. 1/2 c. 0 d. 0 4. This alters the phenotype 5. It would be Mendelian because the gene that causes the condition when mutated is in the nucleus. 6. 0.45 x .05 = .0225 7. The sperm are all of genotype hh se se. The oocytes are of genotype Hh Se se, with the alleles in coupling: H Se h se All sperm are h se oocytes: H Se 49.5% h se 49.5h % H se 0.5% h Se 0.5% Chance offspring like father = 1 (h se) x 49.5 (h se) =

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