Mendelian traits

Single nucleotide polymorphisms Single base-pair changes that are inherited as mendelian traits and might associate with a trait such as susceptibility to disease. 

With completion of the human genome project, the functional and positional cloning of Mendelian traits and diseases can become fairly routine (2). Yet, considerable work still lies ahead even with Mendelian diseases document worldwide variation in mutations, identify the effects of modifier genes on heterogeneity with respect to age of onset and severity, obtain accurate measurements of the penetrance values of different allelic mutations, study the effects of environmental factors on disease expression, and develop appropriate therapies. 

Design analysis based on genetics (linkage study for Mendelian trait, association study for non-Mendelian trait). 

Optimal for Mendelian Traits Optimal for complex traits... 

Goodnow In the mice, when we are generating equivalent kinds of missense mutations that have a Mendehan trait, one of the things we are learning is how easy it is for a simple Mendelian trait with incomplete penetrance and a bit of variability to look not Mendelian. 

Another theme is the spectrum of kinds of genetic variation in terms of the relationship between genetic variation and phenotypes. These range from simple Mendelian traits, to genes of large effect masked by lots of modifiers thrown in, right through to QTLs that contribute small amounts to phenotypic variance. 

McKusick s compendium of Mendelian traits in man lists 793 autosomal dominants, 629 autosomal recessives, and 123 X-linked recessives. 

Jaeger SR, McRae JF, Bava CM, Beresford MK, Hunter D, Jia Y, Chheang SL, Jin D, Peng M, Gamble JC, Atkinson KR, Axten LG, Paisley AG, Tooman L, Pineau B, Rouse SA and Newcomb RD. (2013) A mendelian trait for olfactory sensitivity affects odor experience and food selection. Curr Biol, 23 1601-1605. 

Within a population there is a proportion of individuals who are predisposed to develop cancer, either as an apparently sporadic disease or in response to an environmental challenge, such as exposure to tobacco smoke or ionising radiation. The abnormally high frequency of some tumor types within related members of large famihes provided evidence that cancer is, in some circumstances, a heritable disease. Genetic linkage studies of these famihes has revealed that a number of these cancer syndromes occur as simple Mendelian traits, usuaUy with a highly penetrant dominant pattern of inheritance. 

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