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chapter 9 section 2
genetics crosses
Term | Definition |
---|---|
genotype | the entire genetic makeup of an organism; also the combination of genes for one or more specific trait |
phenotype | an organism's appearance or other detectable characteristics that results from the organism's genotype and the environment |
homozygous | describes an individual that has identical alleles for a trait on both homologous chromosomes |
heterozygous | describes an individual that has two different alleles for a trait |
probability | the liklihood that a possible future event will occur in any given instance of the event; the mathematical ratio of the number of times one outcome of any event is likely to occur to the number of possible outcomes of the event |
monohybrid cross | a cross between individuals that involves one pair of contrasting traits |
punnet square | a graphic used to predict the results of a genetic cross |
genotypic ratio | the ratio of he genotypes that appear in offspring |
phenotypic ratio | the ratio of phenotypes produced by a cross |
testcross | the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype |
complete dominance | a relationship in which one allele is completely dominant |
codominance | a condition in which both allele for a gene are fully expressed |
dihybrid cross | a cross between individuals that have different alleles for the same gene |