Variant allele

The goal of any statistical analysis is inference concerning whether on the basis of available data, some hypothesis about the natural world is true. The hypothesis may consist of the value of some parameter or parameters, such as a physical constant or the exact proportion of an allelic variant in a human population, or the hypothesis may be a qualitative statement, such as This protein adopts an a/p barrel fold or I am currently in Philadelphia. The parameters or hypothesis can be unobservable or as yet unobserved. How the data arise from the parameters is called the model for the system under study and may include estimates of experimental error as well as our best understanding of the physical process of the system. 

Allele variant forms oftheDNA sequence at a specified locus. For example, alleles at a single-nucleotide polymorphism (SNP) are characterized by the nucleotide that is changing. The combination of two alleles at a locus constitutes a genotype. 

Resistance to trimethoprim can be due to the acquisition of plasmid encoded non-allelic variants of the chromosomal DHFR enzyme that are antibiotic unsusceptible. The genes may be part of transposons that then insert into the chromosome. For instance, in gram-negative bacteria the most widespread gene is dhfrl on transposon Tn7. 

Rettie, A. E. etal. (1994). Impaired (S)-warfarin metabolism catalysed by the R144C allelic variant of CYP2C9. Pharmacogenetics, 4, 39 42. 

Sata, F. et al. (2000). CYP3A4 allelic variants with amino acid substitutions in exons 7 and 12 evidence for an allelic variant with altered catalytic activity. Clin. Pharmacol. Ther., 67,48-56. 

Tirona, R. G., Leake, B. F., Merino, G., Kim, R. B., Polymorphisms in OATP-C identification of multiple allelic variants associated with altered transport activity among European-and African-Americans, J. Bid. Chem. 2001, 276, 35669-35675. 

CYP2C9 Multiple allelic variants of CYP2C9 may account for the occurrence of poor metabolizers and increased efficacy of warfarin (84)... 

Sanak M, Pierzchalska M, Bazan-Socha S, Szczeklik A. Enhanced expression of the leukotriene C(4) synthase due to overactive transcription of an allelic variant associated with aspirin-intolerant asthma. Am J Respir Cell Mol Biol 2000 23 290-296. 

S, Papiha SS, Dai R, et al. The human peroxisome proliferator-activated receptor alpha gene identification and functional characterization of two natural allelic variants. Pharmacogenetics 2000 10 321-333. 

Srivastava SK, Singhal SS, Hu X et al. Differential catalytic efficiency of allelic variants of human glutathione S-transferase Pi in catalyzing the glutathione conjugation of thiotepa. Arch Biochem Bio-phys 1999 366 89-94. 

Pandya, U. et al., Activity of allelic variants of Pi class human glutathione S-transferase toward chlorambucil, Biochem. Biophys. Res. Commun., 278, 258, 2000. 

Individual mice express a combinatorial pattern of MUPs (typically at least 7-12 isoforms) reflecting multiple allelic variants and multiple expressed loci (Robertson et al. 1997). Among wild mice, individuals each express a different pattern even when captured from the same population (Payne, Malone, Humphries, Bradbrook, Veggerby, Beynon and Hurst 2001 Beynon et al. 2002), with the exception of very closely related animals that have inherited the same haplotypes from their parents (a 25% chance among outbred sibs, similar to MHC type sharing). The extreme heterogeneity in the sequence of MUPs is mostly confined to strands B, C and D and the intervening turns of the 8-barrel structure (Beynon et al. 2002). 

Haining RL, Hunter AP, Veronese ME, et al. Allelic variants of human cytochrome P450 2C9 baculovirus-mediated expression, purification, structural characterization, substrate stereoselectivity, and prochiral selectivity of the wild-type and I359L mutant forms. Arch Biochem Biophys 1996 333(2) 447 t58. 

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