1. Chapter 4, Heredity and Evolution
Genetic Principles Discovered by Mendel
Mendelian Inheritance in Humans
Non-Mendelian Patterns of Inheritance
Modern Evolutionary History
Definition of Evolution
Factors that Produce and Redistribute Variation
Review of Genetic and Environmental Factors

2. Mendel’s Discoveries Segregation Dominance and Recessiveness
Independent Assortment

3. Principle of Segregation
gamete production Members of each gene pair separate so each gamete contains one member of a pair.
fertilization Full number of chromosomes is restored and members of gene pairs are reunited.

4. Mendelian Inheritance in Humans
Over 4,500 human trains are known to be inherited according to simple Mendelian principles.
The human ABO blood system is an example of a simple Mendelian inheritance.

5. Inherited Genetic Disorders
Dominant disorders are inherited when one copy of a dominant allele is present.
Recessive disorders require the presence of two copies of the recessive allele.
Recessive conditions: cystic fibrosis, Tay-Sachs disease, sickle cell anemia, and albinism.

6. Non-Mendelian Patterns of Inheritance: Polygenic
Polygenic traits are influenced by genes at two or more loci.
Continuous traits have a series of measurable intermediate forms between the two extremes.
Examples: skin color, stature, eye color.

7. Non-Mendelian Patterns of Inheritance: Pleiotropy
A single gene influences more than one phenotype expression.
The rule rather than the exception.
Example: sick-cell anemia, PKU.

8. Modern Evolutionary Theory
Evolution is a two-stage process:
Production and distribution of variation.
Natural selection acting on this variation.

9. Factors That Produce and Redistribute Variation
mutation
gene flow
genetic drift
recombination