1. Copyright © 2009 Pearson Education, Inc. Chapter 8 Chromosome Mutations: Variation in Chromosome Number and Arrangement Copyright © 2009 Pearson Education, Inc.

2. Table 8.1

3. Copyright © 2009 Pearson Education, Inc. Figure 8.1 Non-Disjunction

4. Copyright © 2009 Pearson Education, Inc. Monosomy Results from the loss of one chromosome 2n – 1 Loss of a chromosome in mammals is not tolerated Why do organisms not survive?

5. Copyright © 2009 Pearson Education, Inc. Trisomy Results from the gain of one chromosome 2n + 1 In many cases, the individual can survive Trisomy is common in plants Jimson Weed

6. Copyright © 2009 Pearson Education, Inc. Figure 8.2 The 12 Possible Trisomies in Jimson Weed

7. Copyright © 2009 Pearson Education, Inc. Trisomies in Humans Down Syndrome (47, 21+) Patau Syndrome (47, 13+) Edwards Syndrome (47, 18+)

8. Copyright © 2009 Pearson Education, Inc. Down Syndrome First reported in 1866 1 in 800 live births Physical, physiological, and mental abnormalities Average life expectancy is around 50 years Can arise through non-disjunction in anaphase I or II 75% are during meiosis I 95% are from errors in ovum formation

9. Copyright © 2009 Pearson Education, Inc. Figure 8.4 Down Syndrome

10. Copyright © 2009 Pearson Education, Inc. Figure 8.5

11. Copyright © 2009 Pearson Education, Inc. Figure 8.6 Patau Syndrome Aka Trisomy 13 1 in 19,000 live births Average survival is 3 months Average age of parents is around 32

12. Copyright © 2009 Pearson Education, Inc. Figure 8.7 Edwards Syndrome Aka Trisomy 18 1 in 8,000 live births Average survival is 4 months Average maternal age is 34.7 Most infants are females

13. Copyright © 2009 Pearson Education, Inc. Aneuploidy Statistics David Carr 1971 study of spontaneously aborted fetuses Significant number were because of trisomies Monosomies were rarer Additional findings

14. Copyright © 2009 Pearson Education, Inc. Polyploidy Occurs when there are more than 2 haploid sets of chromosomes Naming is based on the number of sets Triploidy – 3n Tetraploid – 4n Common in plants, not so common in animals Autopolyploidy vs. Allopolyploidy

15. Copyright © 2009 Pearson Education, Inc. Figure 8.8 Polyploidy

16. Copyright © 2009 Pearson Education, Inc. Autopolyploidy Can arise in several ways Autotriploids Autotetraploids Can be induced in the lab by adding colchicine to dividing cells Important to agriculture

17. Copyright © 2009 Pearson Education, Inc. Figure 8.9 Colchicine Induction

18. Copyright © 2009 Pearson Education, Inc. Allopolyploidy Results from hybridizing two closely related species Usually can’t reproduce because can’t produce viable gametes Can be induced in the lab using cochicine

19. Copyright © 2009 Pearson Education, Inc. Figure 8.10

20. Copyright © 2009 Pearson Education, Inc. Figure 8.11

21. Copyright © 2009 Pearson Education, Inc. Endopolyploidy Condition in which only some cells are polyploid in an otherwise diploid organism

22. Copyright © 2009 Pearson Education, Inc. Variation in Internal Composition and Arrangement of Chromosomes Deletions Duplications Inverstions Translocations

23. Copyright © 2009 Pearson Education, Inc. Deletions A missing region of the chromosome

24. Copyright © 2009 Pearson Education, Inc. Figure 8.13a Deletions A missing region of a chromosome Terminal deletion Intercalary deletion

25. Copyright © 2009 Pearson Education, Inc. Figure 8.14

26. Copyright © 2009 Pearson Education, Inc. Figure 8.15 Cri du Chat Syndrome

27. Copyright © 2009 Pearson Education, Inc. Figure 8.13b Duplications The presence of any part of the genetic material more than once in a genome Results from misalignment during synapse Three interesting aspects of duplications Result in gene redundancy May produce phenotypic variation Important for evolution

28. Copyright © 2009 Pearson Education, Inc. Figure 8.17

29. Copyright © 2009 Pearson Education, Inc. Figure 8.13b Duplications are important in evolution Mutations generally can’t happen in genes critical to survival Why? How could gene duplication allow this to happen?

30. Copyright © 2009 Pearson Education, Inc. Figure 8.13b Inversions Occurs when the genetic information within a chromosome gets flipped No loss or gain, just rearrangement Paracentric vs Pericentric The individual is usually not affected But might have problems producing gametes

31. Copyright © 2009 Pearson Education, Inc. Figure 8.19

32. Copyright © 2009 Pearson Education, Inc. Figure 8.20

33. Copyright © 2009 Pearson Education, Inc. Figure 8.21 No Crossing Over

34. Copyright © 2009 Pearson Education, Inc. Figure 8.22

35. Copyright © 2009 Pearson Education, Inc. Figure 8.13d Translocations

36. Copyright © 2009 Pearson Education, Inc. Figure 8.25 Familial Down Syndrome

37. Copyright © 2009 Pearson Education, Inc. Figure 8.26 Fragile Sites