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Topical coverage:

Topical coverage: -DNA and the flow of genetic information (transcription, transcription factors, translation, promotors , splicing) -pedigrees (dominant, recessive, autosomal, sex-linked, maternal, paternal) and probability -mitosis vs. meiosis -independent assortment

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Topical coverage:

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  1. Topical coverage: -DNA and the flow of genetic information (transcription, transcription factors, translation, promotors, splicing) -pedigrees (dominant, recessive, autosomal, sex-linked, maternal, paternal) and probability -mitosis vs. meiosis -independent assortment -linkage (constructing genotypes, making predictions, mapping genes) -sex chromosomes and sex determination -Mutations and the molecular basis of dominant and recessive phenotypes -aneuploidy and non-disjunction

  2. I 1 2 = Menke’s disease II 1 2 3 4 5 = eye flecks ? III 1 2 3 This pedigree shows transmission of two traits: Menke’s disease, and the presence (dominant) or absence (recessive) of golden flecks in the eyes (an X-linked trait). Is this pedigree consistent with Menke’s disease being: Paternally inherited? Maternally inherited? Autosomal dominant? Autosomal recessive? X-linked dominant? X-linked recessive No No No Yes No Yes <- The actual mode of inheritance of Menke’s

  3. I 1 2 M,m(1/2) = Menke’s disease II 1 2 3 4 5 = eye flecks ? III m,Y (1/4) 1 2 3 This pedigree shows transmission of two traits: Menke’s disease, and the presence (dominant) or absence (recessive) of golden flecks in the eyes (an X-linked trait). 1/8 What is the probability that III-3 will have Menke’s disease?

  4. Product Rule: The probability of two or more independent events all occurring (event #1 and event #2 and…) = the product of the individual probabilities Sum Rule: The probability of either one of 2 or more mutually exclusive outcomes (outcome #1 or outcome #2 or…) = sum of the individual probabilities

  5. I 1 2 = Menke’s disease II 1 2 3 4 5 = eye flecks ? III 1 2 3 This pedigree shows transmission of two traits: Menke’s disease, and the presence (dominant) or absence (recessive) of golden flecks in the eyes (an X-linked trait). What is the probability that III-3 will have Menke’s disease with flecks in the eyes? 0

  6. M,m M,m I 1 2 M,m(2/3) M,m = Menke’s disease II 1 2 3 4 5 ? III M,M (1/4) 1 2 3 Let’s imagine that Menke’s disease is autosomal recessive, and that II-5 is a heterozygote What is the probability that III-3 is homozygous for the WT allele of Menke’s disease? 1/6

  7. M,m M,m I 1 2 M,M (1/3) M,m = Menke’s disease II 1 2 3 4 5 ? III M,M (1/2) 1 2 3 Let’s imagine that Menke’s disease is autosomal recessive What is the probability that III-3 is homozygous for the WT allele of Menke’s disease? 1/6 + 1/6 = 1/3

  8. This pedigree shows transmission of two traits: ability to smell methanethiol, and the ability to taste PTC (ability to taste PTC is an autosomal dominant trait). Is this pedigree consistent with ability to smell methanethiol being: Paternally inherited? Maternally inherited? Autosomal dominant? Autosomal recessive? X-linked dominant? X-linked recessive No No No Yes No No

  9. This pedigree shows transmission of two traits: ability to smell methanethiol, and the ability to taste PTC (ability to taste PTC is an autosomal dominant trait). If the two genes are assorting independently, what is the probability that the first child born to III-7 and III-8 will be a non-taster, non-smeller? 1/2X 1/6 = 1/12

  10. This pedigree shows transmission of two traits: ability to smell methanethiol, and the ability to taste PTC (ability to taste PTC is an autosomal dominant trait). If the two genes are linked, what do the chromosomes look like in III-7? PTCmt ptcMT <-Maternal <-Paternal

  11. This pedigree shows transmission of two traits: ability to smell methanethiol, and the ability to taste PTC (ability to taste PTC is an autosomal dominant trait). If the two genes are linked, how would this influence the probability of IV-1 being a non-taster, non-smeller? PTCmt ptcMT <-Maternal <-Paternal

  12. Mitosis vs. Meiosis 2n 1m 1p 2n 1m 1p DNA Replication 2x1m 2x1p DNA Recombination 2x1p 2x1m 2x 1m/p 2x 1m/p 2x 1p/m 2x 1p/m 2x1m 2x1p 2x 1m/p 2x 1p/m 1m 1m 1p 1p 1m 1p/m 1p 1m 1m 1m/p 2n 1p 1p 1n exact copies half as many chromosomes

  13. a a a a A A A A b b b b B B B B a a a a A A A A b b b b B B B B

  14. a a a a A A A A b b b b B B B B a a a a A A A A b b b b B B B B

  15. A A a a B B b b A A a a B B b b a a A A b b B B

  16. A A a a B B b b a A A a B B b b a A a A b b B B

  17. derived genotypes D4S141 1 C B 1 1 2 3 B 2 A C 2 2 3 0 A 2 C (B/C) 1 1 3 3 A 1 B B 1 1 3 5 A D4S115 D4S141 D4S141 D4S111 D4S115 D4S115 Y1P18 1 C B 2 2 3 0 A 1 B B 1 1 3 5 A (1/2) A (B/C) 2 2 3 3 B 1 C (B / 1 1 3 0 A 2 B C) 1 1 3 5 C D4S111 D4S111 R10 Y1P18 Y1P18 D4S98 R10 R10 D4S43 D4S98 D4S98 D4S10 D4S43 D4S43 D4S10 D4S10 HD HD gene likely to reside here HD 2 A (C / 2 2 3 3 B 1 B B) 1 1 3 5 C HD gene likely to reside here Narrowing of the HD region Looking for highly informative recombinants (haplotypes): telomere D4S141 D4S115 D4S111 Y1P18 HD ? R10 D4S98 Where are the informative recombinants? D4S43 D4S10 centromere What Next?

  18. What the frequency of recombination between genes tells us The frequency of recombination is based on percentage of meiotic divisions that result in breakage of linkage between parental alleles C A c a C A c a C A c a C A c a C A c a

  19. What the frequency of recombination between genes tells us Let’s take a step back for a moment C A c a C A c a C A c a C A c a C A c a

  20. What the frequency of recombination between genes tells us Let’s take a step back for a moment …ACGCTACCG… …TGCGATGGC… C A c a …ACGTTACCG… …TGCAATGGC… DNA replication …ACGCTACCG… …TGCGATGGC… C A …ACGCTACCG… …TGCGATGGC… c a …ACGTTACCG… …TGCAATGGC… …ACGTTACCG… …TGCAATGGC…

  21. What the frequency of recombination between genes tells us Let’s take a step back for a moment Imagine that: A = brown eyes a = blue eyes C = B blood type c = O blood type Phenotype of this individual? C A c a Brown eyes B blood type DNA replication C A c a meiosis I & II C A c A Gametes (sperm or eggs) C a c a

  22. What the frequency of recombination between genes tells us Let’s take a step back for a moment Imagine that: A = brown eyes a = blue eyes C = B blood type c = O blood type Phenotype of this individual? C A c a Brown eyes B blood type DNA replication c a Phenotype of this individual? C A c a Blue eyes O blood type c a meiosis I & II meiosis I & II C c a A c c a A c C a a c c a a

  23. What the frequency of recombination between genes tells us Questions for you to think about: 1. If you scored the phenotypes of 20 offspring, and the A & C genes were unlinked, what phenotypes and in what ratios would you expect? 2. If you scored the phenotypes of 20 offspring, and the A & C genes were linked at 10 map units apart, what phenotypes and in what ratios would you expect? Let’s take a step back for a moment Imagine that: A = brown eyes a = blue eyes C = B blood type c = O blood type Phenotype of this individual? C A c a Brown eyes B blood type DNA replication c a Phenotype of this individual? C A c a Blue eyes O blood type c a meiosis I & II meiosis I & II c C A a c c A a c C a a c c a a

  24. What the frequency of recombination between genes tells us Questions for you to think about: 1. If you scored the phenotypes of 20 offspring, and the A & C genes were unlinked, what phenotypes and in what ratios would you expect? 2. If you scored the phenotypes of 20 offspring, and the A & C genes were linked at 10 map units apart, what phenotypes and in what ratios would you expect? 3. What effect would recombination events outside of the A-C interval have on the eye color and blood type traits? 4. What effect would double recombination events within the A-C interval have on the eye color and blood type traits? Let’s take a step back for a moment Imagine that: A = brown eyes a = blue eyes C = B blood type c = O blood type Phenotype of this individual? C A c a Brown eyes B blood type DNA replication c a Phenotype of this individual? C A c a Blue eyes O blood type c a meiosis I & II meiosis I & II c C A a c c A a c C a a c c a a

  25. If A and C are 10 map units apart, how often will we see recombination between A & C? and that 4 out of 5 times (80%) meiosis will proceed like this: This means that 1 out of 5 times (20%) meiosis will proceed like this: C C A A c c a a DNA replication DNA replication C A C A c a c a meiosis I & II meiosis I & II 1 NR 4 NR C A C A C 1 R 4 NR c A A c C a 1 R 4 NR a c a c a 1 NR 4 NR

  26. If A and C are 10 map units apart, how often will we see recombination between A & C? and that 4 out of 5 times (80%) meiosis will proceed like this: This means that 1 out of 5 times (20%) meiosis will proceed like this: C C A A c c a a DNA replication DNA replication C A C A c a c a meiosis I & II meiosis I & II 1 NR 4 NR C A C A C 1 R 4 NR c A A c C a 1 R 4 NR a c a c a 1 NR 4 NR

  27. If A and C are 10 map units apart, how often will we see recombination between A & C? How many Brown eyes B blood type? Imagine that: A = brown eyes a = blue eyes C = B blood type c = O blood type Blue eyes O blood type? Brown eyes O blood type? c a Blue eyes B blood type? c a meiosis I & II 1 NR 4 NR C A C c A a C 1 R 4 NR c c A a A c C c a 1 R 4 NR a a c a c c a a 1 NR 4 NR

  28. What the frequency of recombination between genes tells us Questions for you to think about: 1. If you scored the phenotypes of 20 offspring, and the A & C genes were unlinked, what phenotypes and in what ratios would you expect? 2. If you scored the phenotypes of 20 offspring, and the A & C genes were linked at 10 map units apart, what phenotypes and in what ratios would you expect? Let’s take a step back for a moment Imagine that: A = brown eyes a = blue eyes C = B blood type c = O blood type Phenotype of this individual? C A c a Brown eyes B blood type DNA replication c a Phenotype of this individual? C A c a Blue eyes O blood type c a meiosis I & II meiosis I & II c C A a c c A a c C a a c c a a

  29. What the frequency of recombination between genes tells us Questions for you to think about: 1. If you scored the phenotypes of 20 offspring, and the A & C genes were unlinked, what phenotypes and in what ratios would you expect? 2. If you scored the phenotypes of 20 offspring, and the A & C genes were linked at 10 map units apart, what phenotypes and in what ratios would you expect? 3. What effect would recombination events outside of the A-C interval have on the eye color and blood type traits? 4. What effect would double recombination events within the A-C interval have on the eye color and blood type traits? Let’s take a step back for a moment Imagine that: A = brown eyes a = blue eyes C = B blood type c = O blood type Phenotype of this individual? C A c a Brown eyes B blood type DNA replication c a Phenotype of this individual? C A c a Blue eyes O blood type c a meiosis I & II meiosis I & II c C A a c c A a c C a a c c a a

  30. If A and C are unlinked (i.e., 50 map units apart), how often will we see recombination between A & C? This means that 5 out of 5 times (100%) meiosis will proceed like this: C A c a DNA replication C A c a meiosis I & II 5 NR C A 5 R c A C 5 R a c a 5 NR

  31. If A and C are unlinked (i.e., 50 map units apart), how often will we see recombination between A & C? This means that 5 out of 5 times (100%) meiosis will proceed like this: C A c a DNA replication C A c a meiosis I & II 5 NR C A 5 R c A C 5 R a c a 5 NR

  32. If A and C are 10 map units apart, how often will we see recombination between A & C? How many Brown eyes B blood type? Imagine that: A = brown eyes a = blue eyes C = B blood type c = O blood type Blue eyes O blood type? Brown eyes O blood type? c a Blue eyes B blood type? c a meiosis I & II 5 NR C c A a 5 R c c a A c C 5 R a a c c a a 5 NR

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