Alleles, concepts

There are a number of ways linkage disequilibrium can arise between loci in a population. One possibility is selection If alleles at two (or more) loci confer an advantage to an individual when the alleles occur together, then chromosomes containing these alleles will start to become more frequent in the population than they would otherwise. This increase in this combination of alleles creates linkage disequilibrium. If two populations in different environments experience different levels of selection, the amount of linkage disequilibrium will also probably differ between the populations. This illustrates an important concept While the distance between two loci is constant across populations, the amount of linkage... 

GWA methods are commonly used to associate genetic variants with phenotypic variation, especially in whole-organism systems (e.g., humans) where experimentation is not possible (29,67-69,5). The basic concept is that if a typed variant is causal—or is closely linked with the causal variant that may be untyped—then the phenotype of individuals possessing one allele will... 

The other model, namely the meta-population model, is the island biogeography concept, which refers to reduction of area and fragmentation of populations, threaten species survival and biological diversity. This also explains only that of the land size as a factor for GE model. Both the niche and meta-population theory are the part of bioecogeographic enhanced GE model. In the meta-population model, particular populations may not be so important as long as their alleles and agro-morphological characteristics are present in other linked populations. This useful notion is included in the model, but it is not easy to verify. 

For many years, in about 800 cases with prolonged apnea, one of the present authors (W.K.) has faithfully determined both dibucaine and fluoride inhibition. Many of the fluoride inhibition data were inconsistent with the concept of there being a single, special allele conveying resistance to fluoride inhibition. Fluoride tests may be worth pursuing when the purpose is to conduct research into the genetics or biochemistry of cholinesterase. If the purpose is to explain prolonged apnea after suc-cinylcholine, the fluoride test scarcely repays the effort, because any abnormality of fluoride inhibition also shows up as an abnormality of cholinesterase inhibition by dibucaine (see Table 23). 

The results of molecular studies have demonstrated identical allelic profiles in NE and nonendocrine cells of prostatic carcinomas.These findings support the concept of trans-differentiation of exocrine tumor cells to cells with an NE phenotype. Activation of the ERK/ MAPK pathway appears to be one of the major mechanisms for the transdifferentiation of prostatic carcinoma cells into cells with NE differentiation. 

Several genetic concepts are important for understanding biochemistry and molecular biology. The inherited traits of an individual are due to the genes carried in the cells of that individual. Different versions, alleles, of a gene give rise to different traits. 

Fig. 2. 12-plexed MassEXTEND reaction results. To exemplify the concept, the assay definitions for one of the 12 assays (primer, potential pausing signals, and predicted alleles) are indicated with dotted lines. In the depicted case, the individual is homozygous A. The MassEXTEND primer is fully extended. Each mass signal provides a unique identifier for the presence of an allele in a specific assay. 

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