FA2010 final exam KEY for FA2011 students

# FA2010 final exam - BICD100 Final Exam KEY 1 According to ancestry.com Barack Obama and Sarah Palin are distantly related they are 10th cousins

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1 BICD100 Final Exam KEY 1). According to ancestry.com, Barack Obama and Sarah Palin are distantly related – they are 10 th cousins descended from a common ancestor, John Smith, a pastor and early settler in 17 th century Massachussetts (i.e. there are10 generations separating them from their common ancestor). Of course there are many unknown details of the pedigree linking these two notables to their common ancestor, but let’s suppose the pedigree looks like this >>>>>>>>>>> a. Based on this pedigree, and leaving aside for the moment the implausibility (and general silliness) of this idea, if Obama and Palin had a child together, what would be his/her inbreeding coefficient? (10 pts) (½) 21 + (½) 21 = (½) 20 = 0.00000095 or 9.5 X 10 -7 b. What is the probability that this child would have a condition caused by homozygosity for a recessive mutant allele found in the general population at a frequency of 0.1? (10 pts) f(aa) = qF + q 2 (1-F) = (0.1)(9.5 X 10 -7 ) X (0.1) 2 (0.99999905) = 0.010000085 … insignificant increase over probability due to random mating of 0.01. 2). Ralph Greenspan described breeding of a highly aggressive line of Drosophila that fight a lot. a. From an initial population having an average of 18 fights per hour (standard deviation 10), a subset of flies was chosen with an average of 25 fights per hour (standard deviation 5) and bred together. In the next generation, the average number of fights per hour was 20 (standard deviation 9). What is the narrow sense heritability of fighting tendency (aggression)? (10 pts) h N = (Y o – Y)/ (Y p Y) = (20 – 18)/(25 – 18) = 2/7 = 0.286 b. After 20 generations of selective matings, lines with very high aggression scores were obtained and analyzed for expression levels of all genes in the genome using techniques we did not discuss in class. This led to identification of 42 genes expressed at a higher or lower level in the aggressive line compared to the original line. One of the genes expressed at a higher level in the original line is Cyp6a20, which encodes an enzyme involved in the production of fly pheromones. Reverse genetics tools were used to obtain a Cyp6a20 loss of function mutation, which is recessive. Flies homozygous for this mutation had a 2.5-fold higher frequency of fights than their wild type siblings. Which of the following statements is most clearly supported by these findings? Circle one (8 pts). i. Wild type alleles of Cyp6a20 promotes fighting tendency (aggression) in Drosophila >ii. Wild type alleles of Cyp6a20 inhibit fighting tendency (aggression) in Drosophila iii. Cyp6a20 is “the fighting gene” in Drosophila John Smith 1 2 3 etc. (same pattern’continues, generations 4 - 9) 10 Pali Obama

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2 3). Many studies have found evidence of heritability for speech disorders in humans, which are characterized by difficulty in production or understanding of language in spite of normal intelligence and adequate opportunity to learn language. a. For example, concordance (correlation between members of a twin pair) for speech disorders in a 1995
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## This note was uploaded on 01/16/2012 for the course BICD 100 taught by Professor Nehring during the Fall '08 term at UCSD.

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FA2010 final exam - BICD100 Final Exam KEY 1 According to ancestry.com Barack Obama and Sarah Palin are distantly related they are 10th cousins

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