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15 Cards in this Set
- Front
- Back
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Chromosome
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- A threadlike linear strand of DNA and associated proteins. - Carries genes and functions in the transmission of hereditary information. - Humans have 23 homologous pairs
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Locus
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- A site on a chromosome occupied by a gene
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Gene
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- Occupies a particular locus. - Codes for a particular characteristic of the organism
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Allele
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- One of the alternative states of a gene
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Genotype
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- The genetic constitution of an individual, or groups of individuals in a population
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Phenotype
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- The morphological, physiological, behavioral, or biochemical characteristic of an individual, or groups of individuals in a population
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Genotypic Frequencies
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- P = frequency of MM - H = freq. of MN - Q = freq of NN. - P + H + Q = 1
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Allelic Frequencies Formulas
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- p = freq. of M = P + (.5)H - q = freq. of N = Q + (.5)H - p + q = 1
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Random Mating
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- Mates are chosen without regard to the genotype at the gene locus being considered
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Assortative Mating
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- Non-random mating where like tends to breed with like. - Higher homozygote frequency and lower heterozygote frequency than expected. - No change in allelic frequencies
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Disassortative Mating
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- Non random mating where there is a preference for a different phenotype to mate with. - Heterozygote frequency increases, at expense of homozygotes - Leads to change in allelic frequency since rarer phenotypes are favored and have a higher chance of mating. Rarer allele than increases
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Genotypic Frequency Formulas
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- P = (# of individuals with MM)/(total pop). - H = (# of individuals with MN)/(total pop). - Q = (# of individuals with NN)/(total pop)
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Hardy-Weinberg Principle
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- Allelic frequencies remain constant if there is no genetic drift and an absence of selection, migration, and mutation. - If mating is random the genotypic frequencies are related to allelic frequencies: (p + q)^2 = p^2 + 2pq + q^2 - For autosomal genes, the equilibrium genotypic frequencies at any locus are attained in a single generation providing there is no overlapping of generations
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Hardy-Weinberg Equilibrium
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- Allelic and genotypic frequencies do not change because of random mating. - A.K.A. Neutral Equilibrium
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Violation of strict Assumptions of the Hardy-Weinberg Principle
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- Sickle Cell Anemia in Africa. - Infants are in equilibrium but adults are not. - Surviving adults mate at random and fertility of genotypes are equal, but heterozygous has survival advantage so selection is operating. - Genetic frequencies remain in equilibrium
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