DG - dC tailing
See complementary homopolymeric tailing.

Diabetes
A disease associated with the >absence or reduced levels of insulP1, which is a hormone essential for the transport of glucose to cells.

Diazotroph
An organism that can fix atmospheric nitrogen.

Dicentric chromosome
A chromosome having two centromeres.

Dichogamy
The condition in which the male and the female reproductive organs of a flower mature at different times, thereby making self-fertilization improbable or impossible.

Di-deoxynucleotide (ddNTP)
A deoxynucleotide that lacks a 3'- hydroxyl group, and is thus unable to form the 3'-5' phospho-diester bond necessary for chain elongation. Di-deoxynucleotides are used in DNA sequencing and the treatment of viral diseases. Also sometimes referred to as didN. See nucleotide.

DidN
See di-deoxynucleotide (ddNTP).

DieleCtric constant
The ratio of the permittivity of a medium to that of a vacuum.

Differentially permeable
Referring to a membrane, through which different substances diffuse at different rates; some substances may be unable to diffuse through such a membrane.

Differentiation
(L. differre, to carry different ways) A process in which unspecialized cells develop structures and functions characteristic of a particular type of cell. Development from one cell to many cells, accompanied by a modification of the new cells for the performance of particular functions. In tissue culture, the term is used to describe the formation of different cell types.