Karyotypes and Mutations

1. Karyotypes and Mutations

2. Karyotype • An orderly display of magnified images of the individual’s chromosomes • Shows the chromosomes as they appear in metaphase.

3. What is a Normal Karyotype? • We are supposed to have 46 total chromosomes in each cell (22 pairs of autosomes = 44, + 2 sex chromosomes).

4. Amniocentesis • Take fluid from amniotic fluid around the baby • Amniocentesis • Blood draw • Chorion sac draw

5. Preparing a Karyotype • 1. Use blood cells.

6. Essay: Preparing a Karyotype • 2. Burst RBC (red blood cells-have no nucleus) in hypotonic solution. • Release WBC (white blood cells).

7. Essay: Preparing a Karyotype • Use a centrifuge to separate the white blood cells from the rest of the blood fluid • centrifuge

8. Preparing a Karyotype • 4.Add chemical (colchicine) to stop the chromatids in metaphase (stops spindle fibers from forming) • making a karyotype video

9. Preparing a Karyotype (cont) • 5. Drop on a slide.

10. Preparing a Karyotype (cont) • 5. Take a picture • 6.Sort by size and shape from largest to smallest

11. Types of Karyotypes • Fluorescent to detect a marker showing certain defect karyotype procedure video 4:29

12. Types of Karyotypes • Ideogram: bands locate sites on chromosome

13. Normal Karyotype • WHY? • Is it a Male or a female?

14. Down Syndrome Karyotype • Trisomy 21 • Due to nondisjunction (chrom did not separate evenly)

15. Down Syndrome • Trisomy 21 • Folds over eyes • Sluggish muscles • Mental Problems (IQ often below 50)- but Some much higher

16. Down Syndrome • The most common chromosome number abnormality • Small head, ears, mouth • round face, short neck and arms • flattened nose bridge • small, irregular teeth

17. Down Syndrome • Short Stature • heart defects • susceptibility to respiratory infection , leukemia, ADHD, Alzheimer’s We Are More ALikeThan Different (2:40)

18. As the age of the mother increases above 30, the frequency of Trisomy 21 also increases Does the mother’s age matter?

19. 47 XXY syndrome male testes small (sterile) breast enlargement feminine body contours (wider hips) 1 in 500 to 1,000 newborn males Klinefelter’s Abnormal Sex Chromosomes

20. Klinefelter’s Syndrome • also XXYY, XXXY, XXXXY

21. TURNER SYNDROME • XO (only one X) • Short • often web of skin between neck and shoulders • sterile • poor breast development

22. Turner Karyotype

24. Triploid seedless watermelon Larger polyploid strawberry

25. What about… • MUTATIONS?

26. Chromosomal Mutations • most often brought on by problems that occur during meiosis or by mutagens (chemicals, radiation, etc.) = cancer-causing agent • Often harmful

28. Can you find the changes?

29. DELETION Fragment of the chromosome is lost Could even be fatal

30. Duplication Fragment of one chromosome attaches to a homologous chromosome Maybe no harm.

31. Translocation Fragment reattaches in reverse direction (less likely to produce harm)

33. Translocation • If all parts are transferred evenly, then no harm. • If also duplication or deletion, then changes in genetic make-up.

34. INVERSION • The chromosome breaksin two places, a piece of the chromosome is removed and the chromosome pieces remaining rejoin.

35. Inversions • Inversions, by definition, do not involve loss or gain of chromosomal material. • chromosomal mutations (Mcgraw Hill) • Click mutations

36. INVERSION • Chromosome 10 has an inversion

37. Chromosomes from the father of a child... a portion of chromosome 11 (blue) has been transferred to chromosome 1(yellow). Staining Chromosomes