Term | Definition |
trait | one of 2 or more possible forms of a character; a recognizable feature or characteristic of an organism |
genetics | the science of heredity and of the mechanisms by which traits are passed from parent to offspring |
purebred | type of organism whose ancestors are genetically uniform |
cross | mating of 2 organisms |
law of segregation | Mendel's first law, stating that (1) organisms inherit 2 copies of genes, from each parent, and (2) organisms donate only one copy of each gene in their gametes because the genes separate during gamete formation |
gene | the most basic physical unit of heridity; a segment of nucleic acids that codes for a functional unit of RNA and/ or protein |
allele | one of the alternative forms of a gene that governs a characteristic, such as hair color |
homozygous | describes an individual that has identical alleles for a trait on both homologous chromosomes |
heterozygous | describes an individual that carries two different alleles of a gene |
genome | the complete genetic material contained in an individual or species |
genotype | the entire genetic makeup of an organism; also the combination of genes for one or more specific traits |
phenotype | an organism's appearance or the other detectable characteristics that results from the organism's genotype and the environment |
dominant | in genetics, describes an allele that is fully expressed whenever the allele is present in an individual |
recessive | in genetics, describes an allele that is expressed only when no dominant allele is present in an individual |
punnet square | a graphic used to predict the results of a genetic cross |
mono-hybrid cross | a cross between individuals that involves one pair of contrasting traits |
test cross | cross between an organism with an unknown genotype and an organism with a recessive phenotype |
dihbrid cross | a cross between individuals that have the different alleles for the same gene |
law of independant assortment | the law that states that genes separate independently of one another in meiosis |
probability | the likelihood 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 |
crossing over | exchange of chromosome segments between homologous chromosomes during meiosis 1 |
genetic linkage | tendency for genes located close together on the same chromosome to be inherited together |