04BIS10110152013RecombinLect4

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Unformatted text preview: ct 158 wild-type +++ +++ cv v ct 3 298 4 crossveinless cut wing vermillion eye cv v ct cv v ct cv v ct 1 _____ 1980 progeny BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 37 Drosophilia Trihybrid Cross with double crossovers: 2 F1 + + ct cv v + X cv v ct (arbitrary parental genotype) parental (progeny phenotypes) + + ct 759 cv v + 766 +v+ 73 cv + ct 80 + v ct 140 cv + + 158 +++ 3 cv v ct 1 parentals + + ct cv v + + ++ cv v ct double crossovers BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 38 Drosophilia Trihybrid Cross with double crossovers: 2 + ct + (true gene order) I II II cv + v Calculating RF from crossovers in domain I, II and I & II I, II Calculating (I, cv-ct) Progeny cv + cv + ct + ct + + (80) v (73) v (1) + (3) 157 x100=7.9 1980 (II, ct-v) Progeny (I&II, cv-v) Progeny + cv cv + cv + + cv cv + ct + ct + v (140) + (158) v (1) + (3) 302 x100=15.3 1980 ct + ct + ct + + (80) v (73) v (140) + (158) v (1) x 2* + (3) 459 x100=23.2 1980 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 39 Drosophilia Trihybrid Cross with double crossovers: 2 (cv-ct) (cv-v) 157 x100=7.9 1980 (ct-v) 459 x100=23.2* 1980 7.9 cv 302 x100=15.3 1980 15.3 v ct 23.2 *without multiplying the 4 dc by 2 would give a cv-v distance of 22.97 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez ©2013 BIS101­001, Spring 2013—Genes and Gene Expression, R.L. Rodriguez 40 Interference ­ If crossing over occurs independently in the two regions (i.e., If if the occurrence of one exchange does not alter the probability of the second exchange), the probability of simultaneous exchanges in both regions should be the product of the single crossover probabilities as follows: product Pcv-ct (0.079) X Pct-v (0.153) = Pcv-v (0.012) or 1.2% ct-v (0.153) (1.2% of 1980 total progeny is...
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This note was uploaded on 02/12/2014 for the course BIS 101 taught by Professor Simonchan during the Spring '08 term at UC Davis.

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