Unformatted text preview: xhibit the dominant phenotype, then 36% are recessive Therefore we can say the genotypic frequency of the recessives is = .36 Therefore we know that q2 = .36, so by taking the square root of .36 we get q=.6 If p + q =1 in an ideal popula8on, given that we now know q =.6, this means p must be .4 Therefore the frequency of the dominant allele is = .4 18. A sex linked gene in mice is found in two alleles. In an ideal popula8on, 91% of the females have the dominant phenotype. What percentage of the males has the dominant phenotype? a) 91% b) 70% c) 45% d) 9% e) None of the above 18. A sex linked gene in mice is found in two alleles. In an ideal popula8on, 91% of the females have the dominant phenotype. What percentage of the males has the dominant phenotype? a) 91% b) 70% c) 45% d) 9% e) None of the above Answer: If 91% of the female popula8on exhibit the dominant phenotype, then 9% are recessive Therefore we can say the genotypic frequency of the recessives females is = .09 Therefore we know that q2 = .09, so by taking the square root of .09 we get q=.3 If p + q =1 in an ideal popula8on, given that we now know q =.3, this means p must be .7 Given that we are dealing with sex linked genes we can simply say that p = .7 is equal to 70%, given that the other chromosome would just be a Y See page 68 of the lecture notes for details 19. Gene8c driK refers to ﬂuctua8ons in allele frequencies due to: a) Migra8on. b) Nega8ve or posi8ve selec8on. c) Selec8ve ma8ngs. d) Small popula8on size. e) All of the above are correct. 19. Gene8c driK refers to ﬂuctua8ons in allele frequencies due to: a) Migra8on. b) Nega8ve or posi8ve selec8on. c) Selec8ve ma8ngs. d) Small popula3on size. e) All of the above are correct. You need to understand the idea behind gene8c driK to answer this ques8on: The eﬀect of gene8c driK in large popula8ons is usually negligible whereas in small popula8ons, it predominates. In a small popula8on, gene8c driK results in some alleles becoming more common while others become less common over 8me. This ques8on comes directly from page 79 of Dr. Zitomers Lecture notes  “A small popula8on is subject to random ﬂuctua8ons in allele frequencies that result from small sample sizes.” 20. Two genes that are far apart on a bacterial chromosome are rarely co transformed because: a) They are rarely contained on the same DNA molecule, and, therefore, rarely enter the same cell. b) Recombina8on occurs too...
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 Fall '09
 RichardZitomer
 DNA

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