Base pairs:
A set of two bonded nucleotides on opposite strands of DNA. There are two possible base pairs: C-G and A-T.

A rod-like structure of tightly coiled DNA found in the cell nucleus of plants and animals. Chromosomes are normally found in pairs; human beings typically have 23 pairs of chromosomes.

DNA polymerase:
An enzyme which repairs DNA by facilitating the formation of hydrogen bond between a nucleotide on a broken piece of DNA, such as a nicked or single-stranded piece of DNA as created in the laboratory, and the individual nucleotide it needs to form a complete and stable base pair.

A section of a chromosome, made up of DNA. A given gene provides the information a cell needs to create a specific protein. Collectively, the genes of an organism inform, to some extent, nearly every aspect of the development and formation of that organism. Genes do not, however, dictate behaviors or traits, and neither are genetically informed behaviors and traits incapable of being modified or supplanted; environmental factors also play a very important part in influencing the organism's development and formation.

The degree to which two pieces of DNA match, or complement each other (two pieces of DNA are complementary if their respective nucleotides, in their current order, match C to G and A to T). If one piece of DNA is 100% complementary to another piece of DNA, they demonstrate very high homology; if the pieces are only able to form a handful of base pairs between their corresponding nucleotides, they demonstrate very low homology.

Hybridization Reaction:
A process in which a probe binds to a Southern Blot if the probe's DNA sequence and the DNA on the Southern Blot match.

The center of a cell, where all of the DNA, packaged in chromosomes, is contained.

A radioactive strand of DNA often used to find particular sequences in a Southern Blot.

Restriction enzyme:
An enzyme normally found in bacteria which cuts DNA at specific sites (i.e. each time a specific nucleotide pattern occurs). Because a restriction enzyme always acts upon DNA in the same manner, a map can be made of a restriction enzymes actions on a known set of nucleotides.

The physical manifestation of the information on a gene. If a gene contains the information needed by the organism to create purple eyes, for example, the fact that the organism did indeed have purple eyes is considered a trait of that organism.