General strategies

The availability of the sequence for much of the human genome has made it feasible to initiate large-scale systemic screens to identify common genetic variants in the human population. Recent efforts have focused on identification of single nucleotide polymorphisms (SNPs) or substitutions as they are the most common class of variant. Two strategies have been utilized in screening for SNPs. The "whole-genome scan" strategy for identification of SNPs involves resequencing of random DNA fragments in a relatively small sample of individuals.91 The SNP Consortium has identified over 1.4 million SNPs in such a genomewide effort.92 This resource is useful for building high-density genetic maps. The vast majority of these SNPs are located in noncoding regions of the genome; thus, only a limited number of these variants are likely to have an impact on protein expression or function. A second strategy utilizes direct resequencing of DNA to identify SNPs but focuses on screening the coding and regulatory regions of genes selected because of their potential relevance to common diseases.93-97 The DNA samples screened for variation in both of these strategies are usually obtained from less than 100 unrelated and normally healthy individuals, These individuals are selected to be representative of the general population as the major interest in these screens is identification of common polymorphisms. These population-based screening strategies are quite different from the efforts to identify the variant(s) segregating in a "disease family," where the focus is screening candidate genes in previously localized chromosomal region and the study of related individuals.

10 Ways To Fight Off Cancer

10 Ways To Fight Off Cancer

Learning About 10 Ways Fight Off Cancer Can Have Amazing Benefits For Your Life The Best Tips On How To Keep This Killer At Bay Discovering that you or a loved one has cancer can be utterly terrifying. All the same, once you comprehend the causes of cancer and learn how to reverse those causes, you or your loved one may have more than a fighting chance of beating out cancer.

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