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1、 1. Panacin is a hypothetical drug that you are testing in a large population. You find a continuous dose-response curve in the population. If youre interested in studying genetic variation that contributes to panacin response, what does this suggest to you?(9.0 分分) A.One gene has a major effect on
2、the response to panacin. B.The number of genes involved equals the number of peaks in the dose-response curve. C.There is a threshold of response controlled by a major gene. D.There are likely to be multiple genes involved in the response to panacin. E.There are likely to be multiple genes involved
3、in the response to panacin. 2. Wich of the following best explains variable expression in mitochondrial diseases?(9.0 分分) A.locus heterogeneity B.heterozygosity C.heteroplasmy D.modifierloci E.imprinting 3. Marsha is heteroplasmic for a MELAS mutation. What feature of oogenesis most strongly influen
4、ces the level of mtDNA mutation she will pass to her children, which would influence the clinical expression of disease?(9.0 分分) A.The small number of mitotic divisions during oogenesis B.The long time that elapses between the beginning and the end of oogenesis C.The mitochondrial genetic bottleneck
5、 线粒体遗传瓶颈 D.Energy requirements in the oocyte that influence natural selection for mtDNA mutations E.The low fitness of mtDNA mutations in the oocyte 4. Some tissues are affected by mitochondrial mutations more severely than others. One would expect these tissues would have a high requirement for whi
6、ch of the following?(9.0 分分) A.Protein B.Macromoleculartransport C.Metabolic energy D.Bloodflow E.Free radicals 5. Relative to nuclear DNA, the mutation rate of midochondrial DNA is:(9.0 分分) A.Apparently lower, due to the number of copies of mtDNA per cell B.Approximately equal C.Higher, due to limi
7、tations in DNA repair capabilities D.Lower, due to protection of the mitochondria from environmental insults 6. Sara has mitochondrial encephalomyopathy and stroke-like episodes (MELAS). Her genetic counselor tells her that it is very difficult to predict the severity of the syndrome in any affected
8、 children that she will have. What property of mitochondrial mutations, which is distinct from nuclear mutations, explains this variability in the expression of mitochondrial mutations?(9.0 分分) A.mutation heteroplasmy B.incomplete dominance C.pleiotropy D.epistasis E.the lack of DNA repair enzymes i
9、n mitochondria 7. A child is hospitalized with anemia, jaundice, and cholelithiasis. The lab reveals hemolysis and sickle cell anemia, which occursat a frequency of 1 in 500 individuals. Which of the following represents the frequency of sickle cell carriers in the same population?(9.0 分分) A.0.002 B
10、.0.045 C.0.086 D.0.5 E.0.955 8. If the incidence of cystic fibrosis in the white population in approximately 1 in 4000, what is the carrier frequency?(9.0 分分) A.1/20 B.1/32 C.1/64 D.1/100 E.1/200 9. Disregarding the effects of selection, if one in every400 people in a population has sickle cell dise
11、ase, what is the carrier frequency for the disease mutation?(9.0 分分) A.1in 10 B.1in 20 C.1in 40 D.1in 200 E.1in 1600 10. Some autosomal recessive diseases have a high prevalence in large populations, even though they are often fatal (e.g., sickle cell disease in Africans, cystic fibrosis in European
12、s). Which of the following is the most likely explanation for this phenomenon?(9.0 分分) A.Inbreeding 近亲繁殖 B.High mutation rates in specific populations C.Survival advantage in heterozygous carriers 杂合子优势 D.Survival advantage in individuals who are normal homozygotes E.None of the above mechanisms exp
13、lain the pattern 11. A 19-year-old patient complains of a loss of central vision in both eyes. The onset was less than 6 months ago and has progressed rapidly. The pedigree you construct of the probands family reveals vision loss in the patients mother, all her five siblings, and the probands maternal grandmother. You develop a differential diagnosis of likely disorders that includes which of the following? (10.0 分分) P143 中英文中英文 A. Retinoblastoma B. MELAS syndrome C.Leber hereditary neuropath D. Kearns-Sayre syndrome E. Leigh syndrome
