DNA Related Biological Terms

DNA for which a function has yet to be identified. An elaborate nomenclature has been proposed for this DNA: any stretch of DNA is a nuon; DNA with an evolutionary potential for development of function is a potonuon; DNA that was previously non-functional, or that had a completely different function and has been evolutionarily co-opted for a new function (a process termed exaptation), is a xaptonuon; and a non-co-opted potonuon is a naptonuon.Brosius, J. and Gould, S.J. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 10706-10710; Nowak, R. (1994) Science 263, 608-610; Flam, F.F. (1994) Science 266, 1320

(= multiple-copy single-strand DNA (msDNA))

Mitochondrial DNA; a double-stranded polynucleotide composed of a heavy and a light chain, distinguished by the buoyant densities of the separated strands, which are determined by their G+T content.

A satellite DNA detected in some bacteria that features an oligoribonucleotide attached by the 2'-hydroxy group of an inteRNAl guanylate residue to the 5'-end of an oligodeoxyribonucleotide, while the 3'-end of the DNA moiety is base-paired with the 5'-end of the RNA moiety; both the DNA and RNA possess considerable inteRNAl base-pairing. Inouye, M. and Inouye, S. (1991) Trends Biochem. Sci. 16, 18-21

A satellite DNA detected in some bacteria that features an oligoribonucleotide attached by the 2'-hydroxy group of an inteRNAl guanylate residue to the 5'-end of an oligodeoxyribonucleotide, while the 3'-end of the DNA moiety is base-paired with the 5'-end of the RNA moiety; both the DNA and RNA possess considerable inteRNAl base-pairing. Inouye, M. and Inouye, S. (1991) Trends Biochem. Sci. 16, 18-21

A library that includes all cDNA clones at approximately equal frequencies, unlike most cDNA libraries, which represent cDNAs in rough proportion to the occurrence of their mRNA in the source.Bonaldo, M.F., Lennon, G. and Soares, M.B. (1996) genome Res. 6, 791-806

A souble-stranded form of the nucleic acid which differs from B-, A- and Z-DNA in being less tightly coiled and more extended and having the phosphate backbone on the outside.Allemand, J.F., Bensimon, D., Lavery, R. and Croquette, V. (1998) Proc. Natl. Acad. Sci. USA 95, 14152-14152

A form of DNA in which four oligo(G) sequences, either of the same or of different strands, LINE up either in a parallel, an anti-parallel or in a fold-back (mixed parallel and antiparallel) pattern. The interior of quadruple the helix has four guanine bases in Hoogstein base pairings; each plane of four guanines is separated from the adjacent plane by a Na+ or K+ ion. Although these structures have not been identified cells, they are strongly suspected to cap the ends of chromosomal DNA. see telomerePalecek, E. (1991) Crit. Rev. Biochem. Mol. Biol. 26, 151-226; Yagil, G. (1991) Crit. Rev. Biochem. Mol. Biol. 26, 475-559; Borman, S. (1998) Chem. Eng. News 76 (40) 42-46

Recombinant DNA.

A method to produce improved strains, e.g. salt tolerance of a plant, by gene amplification. random genome fragments are introduced into a vector and grown in a bacterium. The plasmid is then introduced into the original strain at the DNA sequence homologous with the DNA fragment, under conditions that favor tandem repeats. Modified strains are selected first by a resistance marker that was part of the original plasmid, then by cycles of selection under pressure of the desired property, e.g. at high salinity.Mavingui, P., Flores, M., Romero, D., Martinez-Romero, E. and Palacios, R. (1997) Nat. Biotechnol. 15, 564-569