1. PoPuLaTiOn GeNeTiCs

2. PoPuLaTiOn GeNeTiCs ( Heredity was not understood during Darwin’s time) Definition - science of genetic changes in populations. Populations evolve, NOT individuals. Gene pool- total collection of genes in a population at any one time.

3. PoPuLaTiOn GeNeTiCs Microevolution- a change in the frequency of alleles in the gene pool of a population. Ex.: peppered moths: more dark alleles than light alleles.

4. PoPuLaTiOn GeNeTiCs Hardy- Weinberg Equilibrium If a gene pool does not change for many generations, and the frequency of genes is constant, then the population is in “Hardy – Weinberg Equilibrium”. The population is not evolving. (doesn’t occur under typical conditions)

5. PoPuLaTiOn GeNeTiCs Hardy- Weinberg Equilibrium 5 conditions that must occur: 1. population must be large 2. mating must be random 3. no mutations can occur 4. no migration in or out of a population 5. no natural selection can occur

6. PoPuLaTiOn GeNeTiCs Hardy- Weinberg Equilibrium p= freq of dominant allele q= freq of recessive allele p + q = 1 p 2 = freq of homozyg. dom. genotype q 2 = freq of homozyg. rec. genotype 2pq = freq of heterozyg genotype p 2 + 2pq + q 2 = 1

7. PoPuLaTiOn GeNeTiCs Hardy- Weinberg Equilibrium Determine p and q

8. PoPuLaTiOn GeNeTiCs Hardy- Weinberg Equilibrium p= 0.8 q= 0.2 Determine: p2p2 2pq q2q2

9. PoPuLaTiOn GeNeTiCs Hardy- Weinberg Equilibrium Application: PKU caused by a recessive gene 1/10,000 born with PKU.0001 = q 2 ; 0.01 = q p + q = 1; p = 0.99 Q. What % of population are carriers? A. carriers = 2pq 2 (.99) (.01) =.0198 ~.02 = 2%