Genetic determinism

Human perception creates difficulty ia the characterization of flavor people often, if not always, perceive flavors differently due to both psychological and physiological factors. For example, certain aryl thiocarbamates, eg, phenylthiocarbamide, taste exceedingly bitter to some people and are almost tasteless to others (5). This difference is genetically determined, and the frequency of its occurrence differs from one population to another 40% of U.S. Caucasians are nontasters, whereas only 3% of the Korean population caimot perceive the strong bitter taste of the aryl thiocarbamates (6). Similar differences were found ia the sense of smell for compounds such as menthol, carvone, and ethyl butyrate (7). 

Whatever the physiology of odor perception may be, the sense of smell is keener than that of taste (22). If flavors are classed into odors and tastes as is common practice in science, it can be calculated that there are probably more than 10 possible sensations of odor and only a few, perhaps five, sensations of taste (13,21,35—37). Just as a hereditary or genetic factor may cause taste variations between individuals toward phenylthiourea, a similar factor may be in operation with odor. The odor of the steroid androsterone, found in many foods and human sweat, may eflcit different responses from different individuals. Some are very sensitive to it and find it unpleasant. To others, who are less sensitive to it, it has a musk or sandalwood-like smell. Approximately 50% of the adults tested cannot detect any odor even at extremely high concentrations. It is befleved that this abiUty is genetically determined (38). 

Ecogenetics is the study of genetically determined interindividual variation within one species with respect to the response to environmental chemicals or physical environmental factors. 

The inherited diseases of muscle in adults are highly variable. They may be X-linked, autosomal dominant, or autosomal recessive. They may result from germline mosaicism, from a genetically determined predisposition, or from an abnormality in mitochondrial DNA. As a result, these diseases are also variable in age of onset, in the severity of expression of disease, and in the management of the disease. 

Individuals with hereditary low plasma cholinesterase levels (Kalow 1956 Lehman and Ryan 1956) and those with paroxysmal nocturnal hemoglobinuria, which is related to abnormally low levels of erythrocyte acetylcholinesterase (Auditore and Hartmann 1959), would have increased susceptibility to the effects of anticholinesterase agents such as methyl parathion. Repeated measurements of plasma cholinesterase activity (in the absence of organophosphate exposure) can be used to identify individuals with genetically determined low plasma cholinesterase. 

Resistance Reduced susceptibility to a chemical that is genetically determined. 

Hemophilia A Is Due to a Genetically Determined Deficiency of Factor Vlll... 

Genetically determined deficiency of the activity of glucose-6-phosphate dehydrogenase, which produces NADPH, is an important cause of hemolytic anemia. 

Pyrazinamide is a structural analogue of isoniazid and is converted to the active acid derivative intracellularly by a nicotinamidase. Pyrazinamide resistance has been linked to reduced levels of nicotinamidase but the genetic determinants of resistance have not been fully elucidated. 

Association of pigment accumulation with DNA features can inform systematics and applied breeding in crop plants. For carotenoid content among crop plants, maize and tomato are best studied by this technique. Because there is interest in accumulation of various intermediate products in the pathway as well as end products, QTLs were developed for genetic determinates that are not independent of each other. Some QTLs affect multiple pigment contents. 

Cournoyer B, S Watanabe, A Vivian (1998) A tellurite-resistance genetic determinant from pathogenic pseudomonads encodes a thiopurine methyltransferase evidence of a widely conserved family of methyltransferases. Biochim Biophys Acta 1397 161-168. 

Atopic Related to a genetically determined hypersensitivity to environmental allergens allergic. 

Polymorphic metabolism Genetically determined rates of metabolism (fast vs. slow) by selected isozymes of cytochrome P-450 drug-metabolizing enzymes. 

Necheles et al. (N4) first reported a genetically determined homozygous GSH-Px deficiency associated with neonatal jaundice and mild hemolysis. Spontaneous recovery from hemolysis was noted 3 months after birth. Thereafter, several cases with GSH-Px deficiency were reported. Newborn infants exhibit significantly lower red blood cell GSH-Px activity and serum selenium concentrations than adult control subjects, and a significantly positive correlation between selenium concentration and GSH-Px activity has been observed. Furthermore, the addition of selenium stimulates, both in vivo and in vitro, the GSH-Px activity. The neonatal red blood cell GSH-Px deficiency may be partially due to insufficient availability of selenium during pregnancy (P9). Therefore, the diagnosis of GSH-Px deficiency in newborn infants must be made carefully. 

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