| S gene complex | <molecular biology> Genes coding for molecular components of the pollen stigma recognition system in the cabbage genus Brassica). The gene products govern the self incompatibility response and include a glycoprotein found on the stigma surface and a lectin on the pollen grain surface that binds to the stigma glycoprotein. (18 Nov 1997) |
|---|---|
| single-gene diseases | Hereditary disorders caused by a change (mutation) in a single gene. There are thousands of single-gene diseases including achondroplastic dwarfism, huntington disease, cystic fibrosis, sickle cell disease, duchenne muscular dystrophy, and haemophilia. Single-gene diseases typically describe classic simple mendelian patterns of inheritance (as autosomal dominant, autosomal recessive, and x-linked traits) by comparison with polygenic diseases. (12 Dec 1998) |
| single gene disorder | Hereditary disorder caused by a mutant allele of a single gene (for example, Duchenne muscular dystrophy, retinoblastoma, sickle cell disease). Compare: polygenic disorders. (09 Oct 1997) |
| somatic cell gene therapy | The repair or replacement of a defective gene within somatic tissue. (09 Oct 1997) |
| split gene | Non-coding, intervening sequences of DNA that are transcribed, but are removed from within the primary gene transcript and rapidly degraded during maturation of messenger RNA. most genes in the nuclei of eukaryotes contain introns, as do mitochondrial and chloroplast genes. (12 Dec 1998) |
| neurogenic gene | Best described in Drosophila, genes that are required to determine a neuronal fate. Examples: Notch, Delta. (18 Nov 1997) |
| structural gene | A gene that codes for a product (e.g. An enzyme, structural protein, tRNA), as opposed to a gene that serves a regulatory role. (18 Nov 1997) |
| nif gene | <molecular biology> The complex of genes in nitrogen fixing bacteria that code for the proteins required for nitrogen fixation, particularly the nitrogenase. Present as an operon in Klebsiella and carried on plasmid in Rhizobium which inhabit the roots of leguminous plants. (13 Nov 1997) |
| d4dr gene | <molecular biology> A gene which regulates a protein that plays a role in transmitting messages carried by dopamine between neurons (brain cells). A particular form of the gene may have an affect on an individual's personality since it seems to occur in individuals with novelty-seeking behaviour. (09 Oct 1997) |
| dam gene | <molecular biology> A gene that codes for the synthesis of a DNA adenine methylase. (09 Oct 1997) |
| supressor gene | <molecular biology> A gene that can reverse the effect of a mutation in other genes. (14 Nov 1997) |
| syntenic gene | <molecular biology> Genes that are believed to belocated on the same chromosome because they are lost along with a marker gene that is known to be located on that chromosome. (19 Jan 1998) |
| D gene segment | <molecular biology> Diversity gene segment. Part of the gene for the immunoglobin heavy chain, it codes for part of the hypervariable region of the VH domain and is located between the VH and JH segments. There are probably about 20 different D segments. (18 Nov 1997) |
| differential gene expression | Gene expression that responds to signals or triggers; a means of gene regulation; e.g., effects of certain hormones on protein biosynthesis. (05 Mar 2000) |
| diseases, single-gene | Hereditary disorders caused by a change (mutation) in a single gene. There are thousands of single-gene diseases including achondroplastic dwarfism, Huntington disease, cystic fibrosis, sickle cell disease, Duchenne muscular dystrophy, and haemophilia. Single-gene diseases typically describe classic simple Mendelian patterns of inheritance (as autosomal dominant, autosomal recessive, and X-linked traits) by comparison with polygenic diseases. (12 Dec 1998) |