Gene copy number polymorphism, a major source of genetic variation between humans

We have performed a genome wide analysis of gene copy number polymorphisms and report here for the first time that the human genome contains thousands of well-characterized genes at copy numbers different from one maternal and one paternal allele; and that, furthermore, the copy numbers of hundreds of well-characterized genes can vary between two normal healthy humans making this a major source of genetic variation. Groups of genes affected by CNPs include genes involved in signal transduction, oncogenesis, cell adhesion activity and several types of immune response. In contrast to SNPs, which preferentially affect non-coding regions of the genome, copy number polymorphisms of well-characterized and actively expressed genes are very likely to have important biological consequences.

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