1. PEDIGREES

2. The Role of Mutations in Human Heredity
Mutations are accidental changes in genes
They are rare, random and tend to produce recessive alleles
Mutations cause genetic disorders
The inheritance of these disorders, as well as harmless traits, is studied by looking at pedigrees
Family trees that identify individuals with the disease/trait

3. Punnett squares are useful for finding the probabilities of traits expressing themselves within offspring.
A pedigree goes further by tracking the transmission of a trait through generations.
In most pedigrees, generations are identified by Roman numerals (I, II, III…) and individuals are identified by numbers (1, 2, 3…)

4. PEDIGREE SYMBOLS: = Normal Male = Normal female = Affected male
= Affected female
= Carrier male
= Carrier female
Siblings
Parents/mated

5. OTHER PEDIGREE SYMBOLS:
Twins
Deceased

6. So does the shading mean dominant?
What does the shaded individuals mean?
Shading shows what trait is being tracked.
In other words, if the trait being studied is dominant, those who are dominant will be shaded, or if the trait being studied is recessive, those who are recessive will be shaded.
So does the shading mean dominant?

7. One type of pedigree shows only the phenotypes of individuals.

8. Another type of pedigree chart gives information about all of the individuals’ genotypes for a trait.

9. Addams Family Bb bb bb Bb bb Bb Bb bb B_
What is the percent chance the new Addams’ baby will have web feet?

10. WORKSHEETS!!!

11. Hemophilia: A Sex-Linked Trait
Hemophilia is an inherited condition in which the blood clots slowly or not at all
Two genes that encode blood-clotting proteins reside on the X chromosome
Hemophilia is an X-linked recessive disorder
Males develop hemophilia if they inherit one mutant allele from their mother
For females to develop hemophilia, they have to inherit two mutant alleles, one from each parent

12. Royal hemophilia
Started by a mutant allele in Queen Victoria of England
Three of her nine children received the defective allele
They transferred it by marriage to other royal families
Fig. 8.28
Queen Victoria

13. In all, 10 of Victoria’s male descendants had hemophilia
Fig. 8.28
Escaped the disorder

14. Sickle-Cell Anemia: Recessive Trait
Sickle-cell anemia is an autosomal recessive trait in which the protein hemoglobin is defective
Affected individuals cannot properly transport oxygen to their tissues
Fig. 8.29

15. Sickle-Cell Anemia: Recessive Trait
Smooth shape allows for easy passage through capillaries
Irregular shape causes blockage of capillaries
Fig. 8.30
Normal red blood cell
Sickled red blood cell

16. Huntington’s Disease: Dominant Trait
Huntington’s disease is an autosomal dominant trait that causes progressive deterioration of brain cells
Fig. 8.33
It is a fatal disease
However, it persists in human populations because it has a late onset

17. USING THE LEFT POP. PYRAMID; ESTIMATE THE PERCENT OF THE POPULATION BEING BETWEEN 5 & 19 YEARS OLD.
STATE AT LEAST 3 COMPARISONS BETWEEN THE POPULATION PYRAMIDS. BE SPECIFIC