| gene cluster | A set of closely related genes that code for the same or similar proteins and which are usuallygrouped together on the same chromosome. (09 Oct 1997) |
|---|---|
| gene conversion | <molecular biology> A phenomenon in which alleles are segregated in a 3:1 not 2:2 ratio in meiosis. May be a result of DNA polymerase switching templates and copying from the other homologous sequence or a result of mismatch repair (nucleotides being removed from one strand and replaced by repair synthesis using the other strand as template). (18 Nov 1997) |
| gene deletion | The total loss (or absence) of a gene. Gene deletion plays a role in birth defects and in the development of cancer. (12 Dec 1998) |
| gene disorder | Hereditary disorder caused by a mutant allele of a single gene (e.g., Duchenne muscular dystrophy, retinoblastoma, sickle cell disease). Compare polygenic disorders. (05 Mar 2000) |
| gene disruption | Use of both in vitro and in vivo recombination to substitute an easily selected mutant gene for a wild-type gene. (09 Oct 1997) |
| gene divergence | The difference (expressed as a percentage) in the nucleotide sequencesbetween two related genes that developed from the same ancestral gene. (09 Oct 1997) |
| gene dosage | <molecular biology> Number of copies of a particular gene locus in the genome, in most cases either one or two. (18 Nov 1997) |
| gene dosage compensation | The putative mechanism that adjusts the X-linked phenotypes of males and females to compensate for the haploid state in males and the diploid state in females. It is now largely ascribed to lyonization which compensates the mean of the dose but not its variance, which is greater in females. (05 Mar 2000) |
| gene dosage effect | In codominant alleles, the more or less linear relationship between the phenotypic value and the number of genes of one type substituted by another type. (05 Mar 2000) |
| gene duplication | <molecular biology> A class of DNA rearrangement that generates a supernumerary copy of a gene in the genome. This would allow each gene to evolve independently to produce distinct functions. Such a set of evolutionarily related genes can be called a gene family. (18 Nov 1997) |
| gene, evolutionarily conserved | 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) |
| gene families | Groups of closely related genes that makesimilar products. (09 Oct 1997) |
| gene family | <molecular biology> A set of genes coding for diverse proteins which, by virtue of their high degree of sequence similarity, are believed to have evolved from a single ancestral gene. An example is the immunoglobulin family where the characteristic features of the constant domains are found in various cell surface receptors. (18 Nov 1997) |
| gene flow | The movement of genes from one population to another viainterbreeding. (09 Oct 1997) |
| gene frequency | The relative occurence (expressed as a percentage) of a gene in a given population. (09 Oct 1997) |