| A | B |
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| pedigree | a diagram that shows the occurrence of a genetic trait in several generations of a family |
| multiplealleles | more than two allesles (versions of the gene) for a genetic trait |
| meiosis | a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells (gametes or spores) |
| genotype | the entire genetic makeup of an organism; also the combination of genes for one or more specific traits |
| recessive | describes a trait or an allele that is expressed only when two of the alleles for the same characteristic are inherited |
| law of segregation | Mendel's law that states that the pairs of homologous chromosomes separate in meiosis so that only one chromosome from each pair is present in each gamete |
| codominance | a condition in which both alleles for a gene are fully expressed |
| sexual reproduction | Reporduction in which gametes from two parents unite |
| independent assortment | the random distribution of the pairs of genes on different chromosomes to the gametes |
| crossing over | the exchange of genetic material between homologous chromosomes during meiosis; can result in genetic recombination |
| oogenesis | the production, growth, and maturation of an egg, or ovum |
| genetics | the science of heredity and of the mechanisms by which traits are passed from parents to offspring |
| test cross | the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype |
| fertilization | the union of a make and female gamete to form a zygote |
| heterozygous | describes an individual that has two different alleles for a trait |
| asexual reproduction | reproduction that does not involve the union of gametes and in which a single parent produces offspring that are genetically identical to the parent |
| polygenic trait | a characteristic of an organism that is determined by many genes |
