1. Karyotypes & 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

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

7. XX~ female XY~ male

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

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

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

11. Can YOU spot the chromosomal mutation??

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

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

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

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

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

22. 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

23. Can you spot the mutation?

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

25. Look at the karyotype for the mutation

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

27. What is the mutation?
Boy or Girl?

28. Trisomy 13 (Patau syndrome)
Extra fingers or toes
Cleft lip or palate (deformed lips)
Heart and brain structure problems
Die within 1-2 years of age

29. What is the mutation?
Boy or Girl?

30. Turner’s Syndrome 45,X Webbed neck Infertile
Swollen hands & feet at birth
Heart defects

31. Chromosomal Mutations Videos
Visualizing Nondisjunction