1. Chromosome Mutations

2. Look at the karyotype for the mutation

4. A karyotype is an organized profile of a person's chromosomes.
In a karyotype, chromosomes are arranged and numbered by size, from largest to smallest.

5. Karyotypes are done by doctors to diagnose some genetic disorders
Ex: Down syndrome, Turner’s syndrome

6. Karyotypes are done by doctors to diagnose some genetic disorders

7. A normal human karyotype has 46 chromosomes (23 pairs):
#1-22 are called autosomes
#23 are called sex chromosomes

9. XX~ female XY~ male

10. RECALL…What is a mutation?
Any mistake or change in DNA sequence
Mutations can only be inherited if they occur in a gamete or sex cells
Two types: Gene or chromosomal

11. Chromosomal mutation: affects whole or part of a chromosome
Gene mutation:
Changes to the bases in the DNA of ONE gene

12. Chromosomal Mutations
Change in # of chromosomes OR structure of the chromosome
Abnormality detected on karyotype
Five types

13. Can YOU spot the chromosomal mutation??

15. 1) Deletion
Loss of all or part of a chromosome

17. 2) Duplication
Produce extra copies of parts of a chromosome.

19. 3) Inversion
Part of a chromosome breaks out and reinserts backwards.

21. 4) Translocation
Part of a chromosome breaks off & attaches to another chromosome

22. 5) Nondisjunction
Improper separation of homologous chromosomes during meiosis
Results in extra or missing chromosomes in gametes

24. Remember—normally have 2 copies of each
Types of Nondisjunction
Trisomy~ 3 copies of a chromosome
Monosomy~ 1 copy of a chromosome
Remember—normally have 2 copies of each

25. Down Syndrome – Trisomy 21
Intellectual and developmental disabilities
may have heart defects and respiratory problems

26. Trisomy on Sex Chromosomes
XYY Syndrome – Extra Y
XXX Syndrome – Triple X

27. Look at the karyotype for the mutation

28. What is the mutation?
Boy or Girl?

29. What is the mutation?
Boy or Girl?

30. Chromosomal Mutations Videos
Visualizing Nondisjunction