1. Genetic Mutations

2. Mutations … are changes in the genetic material can be good or bad
can be on a single gene or the whole chromosome

3. What is a karyotype? Picture of your chromosomes
Arranged from largest to smallest
quickly identify chromosomal changes

6. 4 Types of Genetic Disorders
Single gene
Change in the DNA sequence
More than 6000 known disorders
Autosomal or sex linked
1 in 200 births
cystic fibrosis, sickle cell anemia, Marfan syndrome, Huntington’s disease

7. Types of Genetic Disorders
Multifactoral
combination of environmental factors and mutations in multiple genes
more complicated
heart disease, high blood pressure, Alzheimer’s disease, arthritis, diabetes, cancer, and obesity

8. Types of Genetic Disorders
Chromosomal
abnormalities in chromosome structure as missing or extra copies or gross breaks and rejoining
Down Syndrome

9. Types of Genetic Disorders
Mitochondrial
rare type of genetic disorder
caused by mutations in the non-chromosomal DNA of mitochondria

10. Dominant genetic disorders
On our chromosomes are a total of about 100,000 genes. Among these 100,000 genes, each person has on average 5-8 bad genes. However, these seldom have any effect at all. But sometimes there are serious errors in our genetic code and these can give us the blueprint for genetic disorder. When we have a serious genetic error, there are three primary ways that the error can be inherited (passed from generation to generation). These three patterns of inheritance are:
Dominant genetic disorders
Recessive genetic disorders
Sex-linked genetic disorders
Genetic Disorders
On our chromosomes are a total of about 100,000 genes. Among these 100,000 genes, each person has on average 5-8 bad genes. However, these seldom have any effect at all. But sometimes there are serious errors in our genetic code and these can give us the blueprint for genetic disorder. When we have a serious genetic error, there are three primary ways that the error can be inherited (passed from generation to generation). These three patterns of inheritance are:
Dominant genetic disorders
Recessive genetic disorders
Sex-linked genetic disorders

11. Dominant Genetic Disorders:
In the dominant genetic disorder pattern of inheritance, one bad gene from either parent will cause the genetic disorder. Since only one bad gene causes the disorder, if either parent has the disorder the chance of the child inheriting the bad gene and developing the disorder is 50% with each conception.

12. Recessive Genetic Disorders:
To develop a recessive genetic disorder both parents must contribute the same defective gene. The parents usually don't have the disorder, but are carriers for the disorder. They carry one defective gene, which is recessive, and one normal dominant gene.

13. Sex-linked Genetic Disorders:
These disorders occur due to errors in the 23rd pair of chromosomes (the chromosomes responsible for gender). These genetic disorders occur only in males. Since males have an XY sex chromosome combination, they are vulnerable to defects on their X chromosome that lacks a partner gene on the Y. These disorders do not appear in females (which are XX) because if one of the X chromosomes has an affected gene, the partner X chromosome carries a normal gene. In females, the other X will compensate any defect on one X. Since males get a Y, there is no compensation. Although the female can carry a defective gene, females do not develop the disorder – they are carriers for the disorder.

14. copyright cmassengale
Mendelian Genetics
4/15/2017
Sex-linked Traits
Traits (genes) located on the sex chromosomes
Sex chromosomes are X and Y
XX genotype for females
XY genotype for males
Many sex-linked traits carried on X chromosome
copyright cmassengale

15. copyright cmassengale
Mendelian Genetics
4/15/2017
Sex-linked Traits
Example: Eye color in fruit flies
Sex Chromosomes
XX chromosome - female
Xy chromosome - male
fruit fly
eye color
copyright cmassengale

16. Sex-linked Trait Problem
Mendelian Genetics
Sex-linked Trait Problem
4/15/2017
Example: Eye color in fruit flies
(red-eyed male) x (white-eyed female) XRY x XrXr
Remember: the Y chromosome in males does not carry traits.
RR = red eyed
Rr = red eyed
rr = white eyed
XY = male
XX = female XR Xr Y
copyright cmassengale

17. Sex-linked Trait Solution:
Mendelian Genetics
4/15/2017
Sex-linked Trait Solution: XR Xr Y
50% red eyed female
50% white eyed male
XR Xr
Xr Y
copyright cmassengale

18. Other Genetic Disorders:
Other genetic disorders do not fall neatly into one of these three patterns. These involve having too many or too few chromosomes.

19. Turners Syndrome 1 in 5,000 births 45 chromosomes X only
#23 Monosomy Nondisjunction

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

21. Cri-Du-Chat Syndrome 1 in 216,000 births 46 chromosomes XY or XX
#5 Deletion of lower arm

22. Cri-Du-Chat Syndrome Moon-shaped face Heart disease Mentally retarded
Malformed larynx
Normal lifespan

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

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

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

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

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

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

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

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

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

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

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

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

35. Down Syndrome Trisomy Down Syndrome 1 in 31,000 births 46 chromosomes
XY=97% XX=3%
#14/21 Translocation
1 in 1,250 births
47 chromosomes XY or XX
#21 Trisomy Nondisjunction

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

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

38. 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

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

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

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

42. ? Jacob’s Syndrome Normal physically Normal mentally
Increase in testosterone
More aggressive
Normal lifespan

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

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

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

46. Triple X Syndrome Normally physically Normal mentally
Learning disabilities
Taller than average
Behavior Problems

47. Huntington’s Chromosome 4 mutation. involuntary twitching or movement
Huntington’s Chromosome 4 mutation *involuntary twitching or movement *onset 40 yrs. *deterioration of the CNS that affects muscle control

48. Sickle-cell Anemia Moon shaped RBC that has low hemoglobin
Shows up more often in African Americans; or whose ancestors once inhabited parts where malaria is a high risk.
Sickle-shaped cells clog capillaries so that cells cannot get oxygen and nutrition
Blood transfusions, pain killers, and drugs
Pain, strokes, jaundice.

49. Cystic Fibrosis Chromosome 7 mutation
Affects mucus, salivary and sweat glands.
Many respiratory problems
Thick, sticky mucus in lungs and digestive tracts.

50. Tay-Sachs No Hex A enzyme
Recessive genetic disorder most often found in Jewish or eastern Europe origin.
Appears in children starting at 6 mo.
Child cannot metabolize a certain lipid which incases the CNS and prevents the brain from expanding.
Fat builds up in the brain causing blindness & paralysis
Death occurs in early childhood

51. Hemophilia Blood has less than 1% of the normal clotting factor
Bleeds longer because blood won’t clot.

52. Color-blindness Cones in the eye do not perceive certain colors
Most common form is reds/greens but some are brown/blue
Seen as gray