Genetic Variation

Allele - Different forms of a gene due to slightly different order of bases

Allele Frequency - Measure of the frequency of a gene variant in a population.

Asexual Reproduction - Reproduction involving only one parent

Co-dominance - Heterozygous individuals show the phenotype of both parents

Crossing Over- During meiosis chromosomes exchange genetic information

Evolution - The change in characteristics of a species over several generations

Founder Effect - Variation loss from a small number establishing a new population

Gene - A length of DNA that holds the instructions for a characteristics

Gene Pool - Refers to the total number of genes of every individual in gene pool

Genetic Drift - Change in allele frequency due to random chance alone

Genotype - Genetic make-up of the organism (e.g. Bb, BB)

Heterozygous - Different forms of the allele are present in the genotype (e.g. Hh)

Homologous Chromosomes - Chromosome pairs (one from each parent) that are similar in length

Homozygous - The same form of the allele is present in the genotype (e.g. HH)

Incomplete Dominance - Heterozygous individuals have a phenotype that is a blend of traits

Independent Assortment - Homologous chromosomes line up at the equator randomly

Lethal Allele - Alleles that produce a gene that kills the offspring

Linked Alleles - Genes located on the same chromosome that are inherited together

Meiosis - The type of cell division which produces gametes

Migration - Movement of organisms into and out of a population

Multiple Alleles - When three or more alleles occupy the same locus (e.g. blood types)

Mutation - A permanent change in the bases on the DNA

Natural Selection - Heritable traits increase an organism’s chances of survival

Pedigree Chart - A family tree which shows biological traits

Phenotype - The physical expression of environmental factors and genotypes

Population Bottleneck - Genetic drift caused by various events, such as a disaster

Pure Breeding - A group of individuals that produce one gamete as they are homozygous

Segregation - The process during meiosis which pairs of alleles are separated

Selective Pressure - Evolutionary force that causes a particular phenotype to be more favorable

Sexual Reproduction - Reproduction involving two parents. Produces genetic variation

Somatic Cells - If a mutation occurs in these cells, it will not be passed onto offspring.