Download PEDIGREE CHARTS

11/17/2016
1
PEDIGREE CHARTS
A family history of a genetic condition
2
What is a pedigree chart?
Can be used to study the transmission of a hereditary condition
3
Symbols used in pedigree charts

Normal male

Affected male
 Normal female

Affected female

Marriage
4
Organising the pedigree chart
A pedigree chart of a family showing 20 individuals
5
Organising the pedigree chart
Generations are identified by Roman numerals
6
Organising the pedigree chart
Individuals in each generation are numbered from the left
7
Interpreting a Pedigree
What can you tell from a pedigree?
Whether a family has an autosomal or sex-linked disease or disorder
• Autosomal disorder: appears in both sexes equally
• Sex-linked disorder: allele is located only on the X or Y chromosome. Most
sex-linked genes are on the X chromosome and are recessive
• So who would have an X-linked disorder more often, boys or girls?
Whether a disorder is dominant or recessive
8
Is this disorder 1) autosomal or sex linked, 2) dominant or recessive?
9
Is this disorder 1) autosomal or sex linked, 2) dominant or recessive?
10
Is this disorder 1) autosomal or sex linked, 2) dominant or recessive?
11
Common Genetic Disorders
Color blindness
Sickle cell anemia
Cystic Fibrosis
Hemophilia
Huntington’s Disease
12
Color Blindness
13
What are blood types?
14
15
Antibodies
16
17
18
Rh Factors
• Scientists sometimes study Rhesus monkeys to learn more about the human
1
11/17/2016
14
15
Antibodies
16
17
18
Rh Factors
• Scientists sometimes study Rhesus monkeys to learn more about the human
anatomy because there are certain similarities between the two species. While
studying Rhesus monkeys, a certain blood protein was discovered. This protein is
also present in the blood of some people. Other people, however, do not have the
protein.
• The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus)
factor.
• If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If
your blood does not contain the protein, your blood is said to be Rh negative (Rh-).
•
2