Genetics and Evolution: Key Concepts for Biology Students

Gene pool

all the genes in a population

Allele

variant of a gene

Genetic drift

chance events affecting allele frequency

Bottle necking

chance extinction causing certain organisms and alleles to die affecting the overall gene frequency

P

dominant gene allele frequency

Q

recessive gene allele frequency

Pˆ2

Homogeneous Dom

2pq

heterozygous dominant

Qˆ2

homogeneous recessive

Combination of p and q

P+q = 1

Allele frequency

percentage of alleles in a population

Natural selection

environmental factors favor certain traits over others allowing those traits to reproduce and pass on their alleles and shifting the overall allele frequency

Artificial selection

humans breeding certain traits to influence allele frequency

Sexual selection

certain traits make organism more likely to mate and pass on alleles

A gene

segment of DNA that contains information to create one functioning product (either protein or RNA) in a cell.

DNA

organized into chromosomes, which are physically distinct pieces of DNA.

Phenotype

observable/ physical trait

Genotype

either homogeneous dom, heterozygous dom, or homogeneous rec, combination/ pair of two genes

Genotype environment interactions

determine the phenotype of an organism

Heredity

Heredity is the process by which genetic information is passed down, while heritable traits are the characteristics that are passed

Codominant alleles

they combine to create a phenotype which shows both allele phenotypes fully.

Incompletely dominant

alleles that combine to create a phenotype which is intermediate between each single allele's phenotype.

Biogeography

how the geographical distribution of species provides evidence for how and when they evolved