| evolutionarily conserved gene | A gene that has remained essentially unchanged throughout evolution. Conservation of a gene indicates that it is unique and essential. There is not an extra copy of that gene with which evolution can tinker. And changes in the gene are likely to be lethal. (12 Dec 1998) |
|---|---|
| J gene | <molecular biology> Gene or genes coding for the Joining segment of polypeptide chain which links the V (variable regions) to the C (constant) regions of both Light and Heavy chains of immunoglobulins. During lymphoid development the DNA is rearranged so that the V genes are linked to the J region sequences. (18 Nov 1997) |
| jumping gene | <molecular biology> Populist term for transposon. (18 Nov 1997) |
| exonuclear gene | <molecular biology> A gene that is not located in the nucleus of the cell. Examples are the genes found in mitochondria and chloroplasts (organelles outside of the nucleus). (09 Oct 1997) |
| expressed gene | <molecular biology> The full use of the information in a gene via transcription and translation leading to production of a protein and hence the appearance of the phenotype determined by that gene. Gene expression is assumed to be controlled at various points in the sequence leading to protein synthesis and this control is thought to be the major determinant of cellular differentiation in eukaryotes. (18 Nov 1997) |
| expression, gene | A gene speaks. When a gene is expressed, the information encoded in the gene is translated into protein or RNA structures present and operating in the cell. Expressed genes include genes that are transcribed into messenger RNA (mRNA) and then translated into protein as well as those genes that are transcribed into RNA (such transfer and ribosomal RNAs) but not translated into protein. (12 Dec 1998) |
| extrachromosomal gene | A gene located outside of the nucleus (e.g., mitochondrial genes). (05 Mar 2000) |
| Y-linked gene | A gene located on a Y chromosome. Synonym: holandric gene. (05 Mar 2000) |
| y-suppressed lethal gene | <genetics> In the fruit fly Drosophila, this is a recessive, lethal gene that kills XO flies but not normal XY male flies. (09 Oct 1997) |
| Z gene | The structural gene for beta-galactosidase. (05 Mar 2000) |
| zygotic effect gene | <genetics> A gene whose phenotype is dependent on the genotype of the zygote, rather than the genotype of the mother. See: maternal effect gene. (18 Nov 1997) |
| zygotic lethal gene | <genetics> A mutated or otherwise defective gene at embryonic or larval stages. (06 May 1997) |
| late gene | <genetics, molecular biology> Gene expressed relatively late after infection of a host cell by a virus, usually structural proteins for the viral coat. (18 Nov 1997) |
| functional gene test | Test for a specific protein iwhich indicates that the corresponding gene is not only present but active. (12 Dec 1998) |
| lethal gene | A gene that produces a genotype that leads to death of the organism before reproduction is possible or that precludes reproduction; for a recessive gene the homozygous or hemizygous state is lethal. (05 Mar 2000) |