Presidential Illness

William Henry Harrison

Zachary Taylor

Grover Cleveland

Woodrow Wilson

Franklin Delano Roosevelt

George H.W. and George W. Bush

King George III (6/4/1738-1/29/1820)

The Madness of King George III

• First signs of dementia in 1788-1789

• Institutionalized at Windsor Castle from 1811-1820

Porphyria

• Caused by a dominant allele that alters the shape of the porphyrin ring in hemoglobin

• Symptoms include insanity, extreme photosensitivity, itchy skin and dark urine

How Do We Know King George Had Porphyria

(and not Arsenic Poisoning?)

Why Are Royal Families Useful For Genetic Research?

Mdekwanton

Mdekwanton Geneology

• All members of the Mdekwanton tribe (Lakota Sioux Nation) receive tax free income due to their ancestry

• Must prove you are at least 25% Mdekwanton by blood

Pedigree Analyses

• Diagrams that demonstrate possible modes of inheritance for various traits through careful organization of demographic and phenotypic data

(i.e. person in question)

How Can Pedigree Diagrams Be Used To Determine The Mode of Inheritance

For A Given Trait?

Four Modes of Inheritance

Autosomal Dominant

• 75% of traits are governed by autosomal dominant inheritance

• As long as one dominant allele is received, the phenotype will be dominant

Pedigree Characteristics of Autosomal Dominant Inheritance• Trait is found in all

generations

• Equal sex-distribution among males and females

Example: Huntington’s Chorea

Huntington’s Chorea Effects

Autosomal Recessive

• Both copies of the recessive allele must be received to express the recessive phenotype

Tay Sachs Disease

• Recessive allele causes buildup of a fatty material called GM2 to build up around nerve cells, inhibiting their function

• Fatal by age 5• No cure• First noted by red spot

in back of retina

Tay Sachs Inheritance

Non-Autosomal/Sex-Linked Dominant Inheritance

• Traits must be carried on either the X or Y chromosome

Pedigree Characteristics of Sex-Linked Dominant Inheritance• Present In Every

Generation• Less frequent in

males due to pleiotropy

• Affected fathers must have affected daughters (if x-linked)

Non-Autosomal/Sex-Linked Recessive Inheritance

• Trait is located on X or Y chromosome

• Trait may be masked by dominant allele if X chromosomes appear as homologous pair (i.e. female)

Pedigree Characteristics of Sex-Linked Recessive Inheritance

• Skipping of generations

• One sex unequally represented in phenotypic outcomes

Hemophilia & The Royal Houses of Europe