GENETIC EVOLUTION

Gene Pool All genetic information from a population of a specific species

Relative Frequency The number of times an allele occurs in gene pool, compared to other alleles in same gene pool

Relative Frequency The number of times an allele occurs in gene pool, compared to other alleles in same gene pool What is the frequency Of black fur?

Relative Frequency The number of times an allele occurs in gene pool, compared to other alleles in same gene pool What is the frequency Of black fur? - 20/50

Relative Frequency The number of times an allele occurs in gene pool, compared to other alleles in same gene pool What is the frequency Of black fur? - 20/50 - 2/5

Single-gene Trait A single-gene trait is controlled by one gene that has two alleles. Variation in this gene leads to only two possible phenotypes Example: Aa, Tt, SS, nn, MM, Jj

Single-gene Trait A single-gene trait is controlled by one gene that has two alleles. Variation in this gene leads to only two possible phenotypes Example: Aa, Tt, SS, nn, MM, Jj In other words: You have It or you don’t have it

Polygenic Traits One polygenetic trait can have many possible genotypes and phenotypes Example: Height, Skin color, eye color

Polygenic Traits One polygenetic trait can have many possible genotypes and phenotypes Example: Height, Skin color, eye color

In the real world Two variables control traits: - Frequency of alleles (Quantity) - Dominant or recessive

Directional Selection Over time, an extreme phenotype is favored over other phenotypes. This causes the curve to shift.

Stabilizing Selection Over time, phenotypes in the center are favored over others

Disruptive Selection Phenotypes at the upper and lower end of curve are favored over the middle

Founder Effect Allele frequencies change as a result of the migration of small populations.

Founder Effect Example: The Amish

Hardy-Weinberg Principle States that allele frequencies in a population will remain constant unless one or more factors cause it to change. Hardy-Weinberg Equation

Hardy-Weinberg Principle P= Frequency of Dominant Alleles q= Frequency of Recessive Alleles P + q =1

Hardy-Weinberg Principle P= Frequency of Dominant Alleles q= Frequency of Recessive Alleles