A<unk>  is a<unk>  gene that alters expression of a<unk>  gene at another locus that in turn causes a genetic<unk> . Whereas medical genetics has tended to distinguish between monogenic traits, governed by simple, Mendelian inheritance, and quantitative traits, with cumulative, multifactorial causes, increasing evidence suggests that<unk><unk> s exist on a continuous spectrum between the two. In the context of<unk><unk> , the terms<unk>  gene' and 'oligogene' have similar meanings, and characterization of a particular locus depends on characterization of the phenotype (effects) that it causes or<unk> . The term<unk>  gene' may be taken to mean a gene in which genetic variation<unk>  the effects of mutation at a major locus, but has no effect on the normal condition, a condition not necessarily met for oligogenic interactions. The study of<unk> s that arise from interactions amongst genes is important for understanding the genetic basis of<unk> . For these purposes, the study of both<unk>  genes and oligogenes are useful.
Human disease modifier gene
Tumor suppressor gene
Germline mutation
Chimeric gene
Ancestry-informative marker
Genetically modified virus
Environmental factor
Gene doping