GLOSSARY :: R ::
Reading Frame: The particular nucleotide sequence that starts at a specific point and is then partitioned into codons. The reading frame may be shifted by removing or adding a nucleotide(s). This would cause a new sequence of codons to be read. For example, the sequence CATGGT is normally read as the two codons: CAT and GGT. If another adenosine nucleotide (A) were inserted between the initial C and A, producing the sequence CAATGGT, then the reading frame would have been shifted in such a way that the two new (different) codons would be CAA and TGG, which would code for something completely different. See DNA, Codon, Mutation, Nucleotide.
Recessive: A genetically determined characteristic that is expressed only in the homozygous recessive condition.
Recombinant DNA (rDNA): DNA formed by the merging of genes (genetic material) into a new combination.
Replication: Reproduction of a DNA molecule (inside a cell). See DNA.
Replicator: An entity which can get itself copied, including any changes it may have undergone. In a broader sense, a replicator is a system which can make a copy of itself, not necessarily copying any changes it may have undergone.
Restriction Enzyme: An enzyme that cuts DNA at a specific site, allowing biologists to insert or delete genetic material. See DNA, Enzyme.
Ribonuclease: An enzyme that cuts RNA molecules into smaller pieces. See RNA.
Ribosome: A molecular machine, found in all cells, which builds protein molecules according to instructions read from RNA molecules. Ribosomes are complex structures built of protein and RNA molecules. See Nucleotide, Protein, RNA.
RNA: Ribonucleic acid; a molecule similar to DNA. In cells, the information in DNA is transcribed to RNA, which in turn is "read" to direct protein construction. Some viruses use RNA as their genetic material. See Protein.