PEDIGREE CHARTS A family history of a genetic

PEDIGREE CHARTS A family history of a genetic condition © 2007 Paul Billiet ODWS

What is a pedigree chart? Pedigree charts show a record of the family of an individual ¢ They can be used to study the transmission of a hereditary condition ¢ They are particularly useful when there are large families and a good family record over several generations. ¢ © 2007 Paul Billiet ODWS

Symbols used in pedigree charts ¢ ¢ ¢ Normal male Affected male Normal female Affected female Marriage A marriage with five children, two daughters and three sons. The eldest son is affected by the condition. Eldest child Youngest child © 2007 Paul Billiet ODWS

Organising the pedigree chart ¢ A pedigree chart of a family showing 20 individuals © 2007 Paul Billiet ODWS

Organising the pedigree chart l Generations are identified by Roman numerals I II IV © 2007 Paul Billiet ODWS

Organising the pedigree chart ¢ ¢ Individuals in each generation are identified by Arabic numerals numbered from the left Therefore the affected individuals are II 3, IV 2 and IV 3 I II IV © 2007 Paul Billiet ODWS

Interpreting a Pedigree ¢ What can you tell from a pedigree? l 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? l Whether a disorder is dominant or recessive

Is this disorder 1) autosomal or sex linked, 2) dominant or recessive? Grandparents Parents Aunts, Uncles Brother You Sex Linked! (in this case allele is recessive and located on the X chromosome)

Is this disorder 1) autosomal or sex linked, 2) dominant or recessive? Grandparents Parents Aunts, Uncles Autosomal dominant! Brother You

Is this disorder 1) autosomal or sex linked, 2) dominant or recessive? Grandparents Parents Aunts, Uncles Autosomal recessive! Brother You

Common Genetic Disorders Color blindness ¢ Sickle cell anemia ¢ Cystic Fibrosis ¢ Hemophilia ¢ Huntington’s Disease ¢ For more info, go to: http: //www. ncbi. nlm. nih. gov/pubmedhealth/

Color Blindness Deficiency to percieve colors Problem with colorsensing pigments in certain nerve cells of the eye About 1 in 10 men have some form of color blindness. Sex-linked disorder

What are blood types? There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible blood type combinations.

How common is your blood type? 46. 1% 38. 8% 11. 1% 3. 9%

Antibodies

Blood Transfusions A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness. Who can give you blood? Universal Donor People with TYPE O blood are called Universal Donors, because they can give blood to any blood type. People with TYPE AB blood are called Universal Recipients, because they can receive any blood type. Rh + Can receive + or Rh - Can only receive Universal Recipient

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-). http: //www. fi. edu/biosci/blood/rh. html A+ AB+ BAB+ ABO+ O-