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| genetics | the branch of biology that studies the ways in which hereditray information is passed from parents to offspring |
| P generation | the starting generation in a breeding experiment |
| F1 generation | the first generation produced in a breeding experiment |
| F2 generation | the second generation produced in a breeting experiment |
| hybrids | the offspring of crosses between pure parents showing contrasting traits |
| dominant | the inherited characteristic that appears in an organism |
| recessive | the inherited characteristic often masked by the dominant characteristic and not seen in an organism |
| Mendel's law of dominance | when an organism is hybrid for a pair of contrasting traits, only the dominant trait can be seen in the hybrid |
| Mendel's law of segregation | factorsthat occur in pairs are separated from each other during gamete formation and recombined at fertilization |
| gene | a distinct unit of heredity material fond in chromosomes; a sequence of nucleotides in DNA that codes for a particulat tRNA, rRNA, or polypeptide |
| alleles | different copis or forms of a gene conrolling a certain trait |
| homozygous | the alleles for a certain trait in an organism are the same |
| heterozygous | if the alleles for a certain trait in an organism are different |
| genotype | the genetic makeup of an organism |
| phenotype | the physical trait that an organism develops as the result of its genotype |
| law of probability | if there are several possible events that might happen, and no one of them is more likely to happen than any other, then they will all happen in equal numbers over a large number of trials |
| Punnet Square | a diagram, used in genetics, to show the results of a cross |
| test cross | an individual of unknown genotype is mated with an individual showing the contrasting recessive trait |
| monohybrid cross | the hybrid cross where only one pair of contrasting traits is being studied |
| dihybrid cross | a breeding experiment involving two different traits |
| Mendel's law of independent assortment | genes for different traits are separated and distributed to gametes independently of one another |
| incomplete dominance | for some organisms, both alleles contribute to the phenotype of a heterozygous individual to produce a trait that is not exactly like either parent |
| codominance | two dominant alleles are expressed at the same time |
| multiple alleles | for some traits, there are more than two alleles in the species |
