1. Nondisjunction disorders
And other abnormal chromosome events

2. Nondisjunction
Failure of sister chromatids or homologous chromosomes to separate during Mitosis or Meiosis (metaphase 1 & 2)
This could result to a condition wherein the daughter cells have an abnormal number of chromosomes; one cell having too many chromosomes while other cell having none.
Trisomic- having three of one type of chromosome (1 extra) 2n+1
Monosomic- having a single chromosome instead of a pair (2n-1) (Turners)
Aneuploidy- is a condition in which the chromosome number is not an exact multiple of the haploid number of a particular species.
Autosomal chromosomes-Any chromosome except for the sex chromosomes. Humans have 44 autosomal chromosomes, or autosomes
Sex chromosomes- the 23rd pair of chromosomes determine the gender of the offspring

3. Probable ancestral haploid number
Polyploidy-the condition in which a normally diploid cell or organism acquires one or more additional sets of chromosomes. Polyploidy is common among plants and has been, in fact, a major source of speciation in the angiosperms
Plant
Probable ancestral haploid number
Chromosome number
Ploidy level
domestic oat 7 42 6n
peanut 10 40 4n
sugar cane 80 8n
banana 11
22, 33
2n, 3n
white potato 12 48
tobacco
cotton 13 52
apple 17
34, 51

4. Human male karyotype, written as 46 XY

5. Human female karyotype, written as 46 XX

6. No abnormal appearance/behavior fertile
Jacob’s syndrome
XYY
No abnormal appearance/behavior
fertile

7. Jacob’s Syndrome 1 in 1,800 births 47 chromosomes XYY only 47XYY
#23 Trisomy Nondisjunction

8. Jacob’s Syndrome Normal physically Normal mentally
Increase in testosterone
Perhaps more aggressive
Normal lifespan

9. Klinefelter’s Syndrome
XXY, male

10. Klinefelter’s Syndrome
1 in 1,100 births
47 chromosomes XXY only
47, XXY
#23 Trisomy Nondisjunction

11. Klinefelter’s Syndrome
Scarce beard
Longer fingers and arms
Sterile
Delicate skin
Low mental ability
Normal lifespan

12. Patau syndrome
47, XX, +13

13. Patau’s Trisomy Syndrome
1 in 14,000 births
47 chromosomes XY or XX
47, +13
#13 Trisomy Nondisjunction

14. Patau’s Trisomy Syndrome
Small head
Small or missing eyes
Heart defects
Extra fingers
Abnormal genitalia
Mentally retarded
Cleft palate
Most die a few weeks after birth

15. Down Syndrome
47, XY, +21

16. Down Syndrome 1 in 1,250 births 47 chromosomes XY or XX
#21 Trisomy Nondisjunction

17. Down Syndrome Short, broad hands Stubby fingers Rough skin
Impotency in males
Mentally retarded
Small round face
Protruding tongue
Short lifespan

18. Edwards Syndrome
47, XY, +18

19. Edward’s Trisomy Syndrome
1 in 4,400 births 47 chromosomes
XX=80% XY=20%
#18 Trisomy Nondisjunction

20. Edward’s Trisomy Syndrome
Small head
Mentally retarded
Internal organ abnormalities
90% die before 5 months of age

21. Turners Syndrome
45, X

22. Turners Syndrome 96-98% do not survive to birth No menstruation
No breast development
No hips
Broad shoulders and neck

23. Trisomy 16, monosomy X
46, X, +16
Not viable beyond 1st trimester

24. Trisomy X 47 XXX symptoms 1/1000
healthy and fertile - cannot be distinguished from normal female except by karyotype

25. Robertsonian Translocation 13-14
Several types, with varying results.

26. Wolf Hirshhorn Syndrome
4p-
Very rare. Affected children are small, with microcephaly and abnormal facies. There are cardiac, renal, and genital abnormalities. Most are stillborn or die in infancy.

27. 5p- site Cri-du-chat Syndrome Moon-shaped face Heart disease
Mentally retarded
Malformed larynx
Normal lifespan

28. Aniridia-Wilms Tumor Syndrome
1 in 50,000,000 births
46 chromosomes XY or XX
#11 Deletion of upper arm

29. Aniridia-Wilms Tumor Syndrome
Mentally retarded
Growth retarded
Blindness
Tumors on kidneys
Short lifespan

30. Thirteen Q Deletion Syndrome
1 in 500,000 births
46 chromosomes XY or XX
#13 Deletion of lower arm

31. Thirteen Q Deletion Syndrome
Mentally retarded
Deformed face
No thumbs
Heart disease
Short lifespan

32. Prader-Willi Syndrome
1 in 5,000,000 births 46 chromosomes
XY=97% XX=3%
#15 Deletion of lower arm

33. Prader-Willi Syndrome
Small bird-like head
Mentally retarded
Respiratory problems
Obesity
Short lifespan

34. Eighteen Q Deletion Syndrome
1 in 10,000,000 births
46 chromosomes XY or XX
#18 Deletion of lower arm

35. Eighteen Q Deletion Syndrome
Mentally retarded
Heart disease
Abnormal hands and feet
Large eyes
Large ears
Normal lifespan

36. Cat-Eye Syndrome 1 in 1,000,000 births 46 chromosomes XY or XX
#22 Deletion of bottom arm

37. Cat-Eye Syndrome Fused fingers and toes Mentally retarded Small jaw
Heart problems
Normal lifespan

38. Four-Ring Syndrome 1 in 10,000,000 births 46 chromosomes XY or XX
#4 Inversion

39. Four-Ring Syndrome Cleft palate Club feet Testes don’t descend
Short lifespan

40. Triple X Syndrome 1 in 2,500 births 47 chromosomes XXX only
#23 Trisomy Nondisjunction

41. Triple X Syndrome
Normally physically Normal mentally
Fertile