| overlap | 1. The lapping of one thing over another; as, an overlap of six inches; an overlap of a slate on a roof. 2. <geology> An extension of geological beds above and beyond others, as in a conformable series of beds, when the upper beds extend over a wider space than the lower, either in one or in all directions. Source: Websters Dictionary (01 Mar 1998) |
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| overlap hybridization | A procedure to find and sequence a gene whose approximate position in a chromosome is known by classical genetic linkage studies. Starting with the known sequence of a gene shown by classical genetics to be near to the novel gene, new clones are picked from a genomic library by hybridisation with a short probe generated from the appropriate end of the known sequence. The new clones are then sequenced, new probes generated and the process repeated until the gene of interest is reached. (18 Nov 1997) |
| overlap index | <cell biology> A measure of the extent to which a population of cells in culture forms multilayers. The predicted amount of overlapping is calculated knowing the cell density, the projected area of the nucleus (usually) and assuming a Poisson distribution. The actual overlap is measured on fixed and stained preparations and the ratio of actual/predicted is derived. A value of 1 implies a random distribution with no constraint on overlapping, normal fibroblasts may have values as low as 0.05. Although a useful measure it does not unambiguously indicate the reason for the effect, which may be contact inhibition of locomotion or differential adhesion of cells between substratum and other cells. (18 Nov 1997) |
| overlapping | <cell biology> In cell locomotion situation in which the leading lamella of one cell moves actively over the dorsal surface of another cell should be distinguished from underlapping. (18 Nov 1997) |
| overlapping gene | <molecular biology> Different genes whose nucleotide coding sequences overlap to some extent. The common nucleotide sequence is read in two or three different reading frames thus specifying different polypeptides. (18 Nov 1997) |
| overlapping reading frame | <molecular biology> Start codons in different reading frames which generate different polypeptides from the same DNA sequence. (09 Oct 1997) |
| vertical overlap | The extension of the upper teeth over the lower teeth in a vertical direction when the opposing posterior teeth are in contact in centric occlusion, the distance that teeth lap over their antagonists vertically, especially for the distance that the upper incisal edges drop below the lower ones, but may also describe the vertical relations of opposing cusps, the relationship of the maxillary incisors to the mandibular incisors when the incisal edges pass each other in centric occlusion. Synonym: overbite. (05 Mar 2000) |
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| horizontal overlap | The projection of the upper anterior and/or posterior teeth beyond their antagonists in a horizontal direction. Synonym: overjet, overjut. (05 Mar 2000) |