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Announcements

Announcements. Exam 1 is on Monday Multiple choice: 15-20 questions Matching: 8-10 questions Problems: 4-6 multipart problems (probably ~50% of total points) Multiple choice/matching problems from lecture, key terms/concepts, and homeworks (covers reading up through Chapter 5)

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Announcements

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  1. Announcements Exam 1 is on Monday Multiple choice: 15-20 questions Matching: 8-10 questions Problems: 4-6 multipart problems (probably ~50% of total points) Multiple choice/matching problems from lecture, key terms/concepts, and homeworks (covers reading up through Chapter 5) Problems similar (NOT IDENTICAL) to Homeworks 1-3 Homework keys and term lists are all on the course website Bring a #2 pencil! You may use a regular calculator, but no phones allowed

  2. BIO 304 Lecture 9

  3. At which stage of meiosis does crossing over occur? ✓ 1. Prophase I 2. Prophase II 3. Metaphase I 4. Metaphase II 5. Telophase I 6. Telophase II

  4. Single and double crossovers

  5. If a dihybrid test cross produces 30% recombinant progeny, EACH parental class must represent ________% of the progeny. 1. 15 2. 30 ✓ 3. 35 4. 50 5. 70

  6. The three-point test cross: PURPOSE: PROCEDURE:

  7. Example 3-point test cross: 3 Drosophila alleles (autosomal): eye color: v (vermillion) or v+ (wild type, red) wing veins: cv (no cross vein) or cv+ (wild type) wing edges: ct (cut) or ct+ (wild type) What is the order of the three genes and the distances between them? P v+ /v+cv /cv ct/ct X v/vcv+/cv+ ct+ /ct+ F1 trihybridv+ /vcv+ /cv ct+ /ct TEST CROSS: v+ /vcv+ /cv ct+ /ctX v/vcv/cv ct/ct F1 trihybrid female tester male

  8. F2 progeny:

  9. Step 1: identify non-crossover classes:

  10. Step 2: identify double crossover classes

  11. Step 3: calculate recombinant frequencies:

  12. Recombinant frequency for v and cv

  13. Recombinant frequency for v and ct

  14. Recombinant frequency for cv and ct

  15. Step 4: construct the map Recombination frequency v and cv: 18.5 Recombination frequency v and ct: 13.2 Recombination frequency cv and ct: 6.4

  16. Short cut: using double recombinants to deduce gene order Double recombinants have the middle gene“flipped” relative to parental arrangement: parentals: vcv+ ct+ v+cv ct DCO’s: vcv+ ct v+cv ct+

  17. How confident do you feel about your mastery of the material for the exam? 1. Very confident 2. I understand almost everything, but need to go over a few topics 3. I'm sure I'll understand everything once I cram this weekend 4. Not very confident

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