A nonregulatory agency which has oversight of research activities that the agency funds.

A nonregulatory agency which has oversight of biotechnology research activities that the agency funds.

The differential survival and reproduc- tion of organisms with genetic characteristics that enable them to better utilize environmental resources.

A procedure for making a DNA probe in which a DNA fragment is treated with DNase to produce single-stranded nicks, followed by incorporation of radioactive nucleotides from the nicked sites by DNA polymerase I.

During extraction of plasmid DNA from the bacterial cell, one strand of the DNA becomes nicked. This relaxes the torsional strain needed to maintain supercoiling, producing the familiar form of plasmid. (See Plasmid.)

See National Institutes of Health.

A membrane used to immobilize DNA, RNA, or protein, which can then be probed with a labeled sequence or antibody.

The conversion of atmospheric nitrogen to biologically usable nitrates.

The purines (adenine and guanine) and pyrimidines (thymine, cytosine, and uracil) that comprise DNA and RNA molecules.

The enlargement or swelling on roots of nitrogen- fixing plants. The nodules contain symbiotic nitrogen- fixing bacteria. See Nitrogen fixation.

An organism which is affected by an interaction for which it was not the intended recipient.

See Northern hybridization.

(Northern blotting). A procedure in which RNA fragments are transferred from an agarose gel to a nitrocellulose filter, where the RNA is then hybridized to a radioactive probe. (See Hybridization.)

See National Science Foundation.

A class of enzymes that degrades DNA and/or RNA molecules by cleaving the phosphodiester bonds that link adjacent nucleotides. In deoxyribonuclease (DNase), the substrate is DNA. In endonuclease, it cleaves at internal sites in the substrate molecule. Exonuclease progressively cleaves from the end of the substrate molecule. In ribonuclease (RNase), the substrate is RNA. In the S1 nuclease, the substrate is single-stranded DNA or RNA.

The two nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are made up of long chains of molecules called nucleotides. See DNA, RNA, Nucleotides.

The term used by Friedrich Miescher to describe the nuclear material he discovered in 1869, which today is known as DNA.

A building block of DNA and RNA, consisting of a nitrogenous base linked to a five carbon sugar. (See Nucleoside analog.)

A synthetic molecule that resembles a naturally occuring nucleoside, but that lacks a bond site needed to link it to an adjacent nucleotide. (See Nucleoside.)

A building block of DNA and RNA, consisting of a nitrogenous base, a five-carbon sugar, and a phosphate group. Together, the nucleotides form codons, which when strung together form genes, which in turn link to form chromosomes. (See Chromosome, Codon, Complementary nucleotides, Dideoxynucleotide, DNA, Gene, Oligonucleotide, RNA.)

The membrane-bound region of a eukaryotic cell that contains the chromosomes.