| genetic locus | <genetics> The position of a gene in a linkage map or on a chromosome. (18 Nov 1997) |
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| marker locus | A locus on a chromosome or in a stretch of DNA that can be identified (e.g., a restriction fragment length polymorphism) and can serve in linkage analysis and in the isolation of a disease gene. See: linkage marker. (05 Mar 2000) |
| cis-acting locus | A section of DNA that affects the activity of DNA sequences on that same molecule of DNA. (05 Mar 2000) |
| complex locus | A set of closely linked genetic loci with a common function, as in the major histocompatibility complex locus. (05 Mar 2000) |
| W locus | <molecular biology> Mouse coat colour locus, equivalent to the kit proto-oncogene, that encodes a receptor tyrosine kinase essential for development of haemopoietic and germ cells. (18 Nov 1997) |
| multi locus enzyme electrophoresis | Inhibition of translation of the transcript of a transposase gene by a multicopy plasmid with suitable inhibitory gene. The plasmid inhibits transposition events in the host bacterium. (18 Nov 1997) |
| multi-locus probe | A probe that hybridizes to anumber of different sites in the genome of an organism. (09 Oct 1997) |
| X-linked locus | Any locus that in normal karyotypes is borne on the X chromosome. (05 Mar 2000) |
| sex-linked locus | Any locus that in normal karyotypes is borne on a heterosome; commonly but incorrectly applied to an X-linked locus. (05 Mar 2000) |
| Y-linked locus | Any (haploid) locus that in normal karyotypes is borne on the Y chromosome. The known content is so far small. (05 Mar 2000) |
| locus | <genetics> The site in a linkage map or on a chromosome where the gene for a particular trait is located. Any one of the alleles of a gene may be present at this site. (18 Nov 1997) |
| locus ceruleus | A shallow depression, of a blue colour in the fresh brain, lying laterally in the most rostral portion of the rhomboidal fossa near the cerebral aqueduct; it lies near the lateral wall of the fourth ventricle and consists of about 20,000 melanin-pigmented neuronal cell bodies whose norepinephrine-containing axons have a remarkably wide distribution in the cerebellum as well as in the hypothalamus and cerebral cortex. Synonym: substantia ferruginea, locus cinereus, locus ferrugineus. (05 Mar 2000) |
| locus cinereus | A shallow depression, of a blue colour in the fresh brain, lying laterally in the most rostral portion of the rhomboidal fossa near the cerebral aqueduct; it lies near the lateral wall of the fourth ventricle and consists of about 20,000 melanin-pigmented neuronal cell bodies whose norepinephrine-containing axons have a remarkably wide distribution in the cerebellum as well as in the hypothalamus and cerebral cortex. Synonym: substantia ferruginea, locus cinereus, locus ferrugineus. (05 Mar 2000) |
| locus coeruleus | Bluish region in the superior angle of the fourth ventricle floor, corresponding to melanin-like pigmented nerve cells which lie lateral to the ponto-mesencephalic central gray (griseum centrale). It is also known as nucleus pigmentosus pontis, locus cinereus, and locus ferrugineus. (12 Dec 1998) |
| locus control region | A regulatory region first identified in the human beta-globin locus but subsequently found in other loci. The region is believed to regulate transcription by opening and remodeling chromatin structure. It may also have enhancer activity. (12 Dec 1998) |