1. What is a Gene?
Gene = a segment of DNA that codes for a protein that controls a trait.
Humans have approximately 30,000 genes
We have 2 copies of
each gene (one on each chromosome
we inherited from our parents).
Each gene has different forms . . .
Allele –one of the many forms of a gene.

2. Examples of Genes and Alleles in Pea Plants
Gene – Seed Shape
Alleles: _____________
_____________
Gene – seed color
Gene – flower color

3. Chromosomes occur in pairs because offspring inherit one from each parent
*We have 46 Chromosomes
(23 pairs of chromosomes)
Chromosomes are made of genes
Circle one gene.
What are the 2 alleles for that gene?
*Each chromosome is made up of DNA that contains hundreds to thousands of GENES.
*HIERARCHY: CHROMOSOMES  CONTAIN DNA  MADE OF GENES  CODE FOR A PROTEIN  MAKE TRAITS

4. Dominant vs. Recessive
NOT ALL ALLELES ARE EXPRESSED! Some alleles are dominant, while others are recessive

5. Description More Info Examples
Dominant
Alleles
This trait always shows up in an organism if it is present
*These usually code for a protein so they are the “normal” form of a gene.
-Widows Peak
-free earlobes
 REPRESENTED WITH CAPITAL LETTER
Recessive
This trait only shows up if there is no dominant allele present
*These usually code for a different protein, or deactivate the “normal” protein.
-No widow’s peak
-attached earlobes
 REPRESENTED WITH LOWERCASE LETTER

6. WHAT HAPPENS IF WE CHANGE OUR DNA?

7. Don’t let this happen to you!!

8. Changes in DNA that affect genetic information
MUTATIONS
Changes in DNA that affect genetic information

9. Gene Mutations Point Mutations – changes in one or a few nucleotides
Substitution
THE FAT CAT ATE THE RAT
THE FAT HAT ATE THE RAT
Insertion
THE FAT CAT XLW ATE THE RAT
Deletion
THE FAT ATE THE RAT

10. Gene Mutations
Frameshift Mutations – shifts the reading frame of the genetic message so that the protein may not be able to perform its function.
Insertion
THE FAT CAT ATE THE RAT
THE FAT HCA TAT ETH ERA T
Deletion
TEF ATC ATA TET GER AT H H

11. Chromosome Mutations
Changes in number and structure of entire chromosomes
What do scientists use to identify these type of mutations?
Original Chromosome ABC * DEF
Deletion AC * DEF
Duplication ABBC * DEF
Inversion AED * CBF
Translocation ABC * JKL
GHI * DEF

12. Your cells have autosomes and sex chromosomes.
Your body cells have 23 pairs of chromosomes.
Homologous pairs of chromosomes have the same structure.
For each homologous pair, one chromosome comes from each parent.
Chromosome pairs 1-22 are autosomes.
Sex chromosomes, X and Y, determine gender in mammals.

13. Molecular Techniques
By investigating body tissue, scientists can detect problems.
Genetic problems can be identified by defective proteins/enzymes or a negative affect on the bodies metabolism.
Genes can be studied directly

14. Electrophoresis (DNA fingerprinting)

15. How do they get the chromosomes?
Chorionic villus sampling
Amniocentesis

16. Karyotypes
a set of photographs of chromosomes grouped in order in pairs from one cell.
What are some observations we could make from this karyotype?

17. Male vs. Female Males have XY sex chromosomes.
Females have XX sex chromosomes
The Y chromosome carries very few genes essential for life.
The X chromosome is a much longer DNA molecule and contains many, many genes that are needed for cells to function.

18. Karyotype Notation A short-hand way to write a person’s karyotype.
Total # of chromosomes, sex chromosomes, extra or missing chromosomes
Normal Female
46XX
Normal Male
46XY

19. Karyotype Notation

20. Significance of Mutations
1. Most are neutral
Eye color
Birth marks
2. Some are harmful
Sickle Cell Anemia
Down Syndrome
3. Some are beneficial
Sickle Cell Anemia to Malaria
Immunity to HIV

21. What Causes Mutations?
There are two ways in which DNA can become mutated:
1. Mutations can be inherited.
Parent to child
2. Mutations can be acquired.
Environmental damage
Mistakes when DNA is copied
Non-disjunction-failure of chromosomes to separate properly during Meiosis.

22. What are we making during Meiosis?
In your own words what is a non-disjunction?

23. Genetic Disorders
an illness caused by one or more abnormalities in the genome, especially a condition that is present from birth.
Conditions may or may not be inherited.
Mutations occur all the time in every cell in the body.
Each cell, however, has the remarkable ability to recognize mistakes and fix them before it passes them along to its descendants.
But a cell's DNA repair mechanisms can fail, or be overwhelmed, or become less efficient with age.

24. Turners Syndrome 45 chromosomes; have only 1 X chromosome #23 Monosomy
Caused by a nondisjunction, if a pair of sex chromosomes fails to separate during the formation of an egg or sperm
Affects1 in 2,500 newborns
45 chromosomes; have only 1 X chromosome
#23 Monosomy
girls fail to go thru puberty

25. Turners Syndrome
96-98% do not survive to birth
stocky appearance
short webbed neck
Other medical symptoms include:
lymphedema (swelling of hands and feet)
heart and/or kidney defects
high blood pressure
infertility (inability to have children)

26. Cri-Du-Chat Syndrome Estimated 1 in 20,000-50,000 newborns
These children have a deleted portion of chromosome number 5.
Estimated 1 in 20,000-50,000 newborns
Found in ALL ethnic backgrounds
Not inherited
Can be XY or XX
#5 Deletion

27. Cri-Du-Chat Syndrome Cry that is high-pitched and sounds like a cat
Downward slant to the eyes
Low birth weight and slow growth
Low-set or abnormally shaped ears
Mental handicap (intellectual disability)
Partial webbing or fusing of fingers or toes
Slow or incomplete development of motor skills
Small head (microcephaly)
Small jaw (micrognathia)
Wide-set eyes

28. WAGR Syndrome 1 in 500,000 children under age 15
The condition results from a deletion on chromosome 11 resulting in the loss of several genes
1 in 500,000 children under age 15
7 in 1000 cases have Wilms Tumor
46 chromosomes XY or XX
#11 Deletion of upper arm

29. Aniridia-Wilms Tumor Syndrome
Predisposed to Wilms kidney tumor
Mentally handicapped
Severe childhood obesity
Growth retardation
Blindness
Tumors on kidneys
Short lifespan
Missing the iris of the eye

30. Thirteen Q Deletion Syndrome
600 cases worldwide
1st diagnosed 20 years ago
46 chromosomes
Affects 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
Prader-Willi syndrome is caused by a gene missing on part of chromosome 15. Normally, your parents each pass down a copy of this chromosome. Most patients with Prader-Willi syndrome are missing the genetic material on part of the father's chromosome.
1 in 15,000 live births 46 chromosomes
XY=97% XX=3%
#15 Deletion of lower arm

33. Prader-Willi Syndrome
Low muscle tone
Short stature
Incomplete sexual development
Cognitive disabilities
Problem behaviors
Chronic feeling of hunger
Obesity
Shorter lifespan

34. Eighteen Q Deletion Syndrome
1 in 40,000 newborns
Estimated 100 babies per year
46 chromosomes XY or XX
#18 Deletion of lower arm

35. Eighteen Q Deletion Syndrome
Symptoms correlate with the size of the deletion
Mentally handicapped
Heart disease
Abnormal hands and feet
Large eyes
Large ears
Normal lifespan

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

37. Cat-Eye Syndrome Normal to severe malformations Fused fingers and toes
Mentally handicapped
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. Trisomy 21 Down Syndrome Down Syndrome
1 in 31,000 births 46 chromosomes
XY=97% XX=3%
#14/21 Translocation
1 in 850 newborns
Estimated 250,000 people are affected in the US
47 chromosomes XY or XX
#21 Trisomy Nondisjunction

41. Down Syndrome Short, broad hands Stubby fingers Rough skin
Impotency in males
Mentally handicapped
Cognitive delays
Small round face
Protruding tongue
Short lifespan
Increased risk of developing Alzheimer disease

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

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

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

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

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

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

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

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

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

51. Triple X Syndrome Normally physically Normal mentally Fertile
Short lifespan

52. Cystic Fibrosis (CF)
Clogs the lungs and leads to life-threatening lung infections.
Obstructs the pancreas and stops natural enzymes from helping the body break down food and absorb vital nutrients
Fluid in lungs, potential respiratory failure
Common among Caucasians
1 in 20 are carriers
Therefore is it dominant or recessive?

53. Cystic Fibrosis (CF) Monogenic
Cause: deletion of only 3 bases on chromosome 7
Estimated in 30,000 children and adults in the U.S.
70,000 people worldwide

54. Muscular Dystrophy X-linked or autosomal genetic disorder.
Muscular dystrophy is a disease in which the muscles of the body get weaker because of a lack of a certain protein
Can be passed on by one or both parents, depending on the form of MD
Symptoms:
Muscle weakness that slowly gets worse
Delayed development of muscle motor skills
Difficulty using one or more muscle groups
Eyelid drooping (ptosis)
Loss of strength in a muscle or group of muscles as an adult
Loss in muscle size
Problems walking (delayed walking)

55. Huntington’s Disease
Huntington's disease (HD) is an inherited, degenerative brain disorder which results in an eventual loss of both mental and physical control.
The disease is also known as Huntington's chorea. Chorea means "dance-like movements" and refers to the uncontrolled motions often associated with the disease.

56. Hemophilia, the royal disease
Hemophilia is the oldest known hereditary bleeding disorder.
Caused by a recessive gene on the X chromosome.
There are about 20,000 hemophilia patients in the United States.
One can bleed to death with small cuts.
The severity of hemophilia is related to the amount of the clotting factor in the blood. About 70% of hemophilia patients have less than one percent of the normal amount and, thus, have severe hemophilia.

57. ALS (Amyotrophic Lateral Sclerosis, or Lou Gehrig’s disease)

58. the disease strikes people between the ages of 40 and 70, and as many as 30,000 Americans have the disease at any given time
This monogenic mutation is believed to make a defective protein that is toxic to motor nerve cells.
A common first symptom is a painless weakness in a hand, foot, arm or leg, other early symptoms include speech swallowing or walking difficulty

59. Designer Baby

60. Chromosome Mutations Cri-du-chat
Deletion of material on 5th chromosome
Characterized by the cat-like cry made by cri-du-chat babies
Varied levels of metal handicaps

61. Sex Chromosome Abnormalities
Klinefelter’s Syndrome
XXY, XXYY, XXXY
Male
Sterility
Small testicles
Breast enlargement

62. Sex Chromosome Abnormalities
XYY Syndrome
Normal male traits
Often tall and thin
Associated with antisocial and behavioral problems

63. Sex Chromosome Mutations
Turner’s Syndrome X
Female
sex organs don't mature at adolescence
sterility
short stature

64. Sex Chromosome Mutations
XXX
Trisomy X
Female
Little or no visible differences
tall stature
learning disabilities
limited fertility

65. What’s an Autosome? Autosome: refers to chromosomes 1-22
Ex: Autosomal disorders: gene for the disease is found on chromosomes 1-22
Autosomal Recessive Inheritance
Must inherit two copies of the disorder to be affected
Healthy is dominant (HH or Hh)
Disease is recessive (hh)
Ex: Cystic fibrosis, PKU, Albinism, Sickle cell anemia
Autosomal Dominance Inheritance
Only need to inherit one copy of the disorder to be affected
Disease is dominant (HH or Hh)
Healthy is recessive (hh)
Ex: Familial hypercholesterolemia (also called FH), Huntington’s disease, Neurofibromatosis

66. Autosomal Dominance Inheritance
Disease is dominant (FF or Ff)
Homozygous dominant: early death and don’t survive to reproduce
Heterozygous live into adulthood
Healthy is recessive (ff)
ex: Paul has familial hypercholesterolemia and Stacy is healthy. The two have 3 children. After testing, the middle child is the only healthy child. f f F f F f
Key
F = FH disease
f = healthy F
disease
disease f f f f f
healthy
healthy

67. Autosomal Dominance Inheritance
Huntington’s disease is a dominant disorder found on chromosome 4. Betty and Marcus met at a support clinic they have been attending to help them cope with the knowledge of their illness with Huntington’s disease. They would like to know the risk of having a healthy child, now that Betty is pregnant. H h H H H h
Key
H = Huntington’s disease
h = healthy H
disease
disease H h h h h
disease
healthy