Copy-number Variation - Identification

Identification

Copy number variation can be discovered by cytogenetic techniques such as fluorescent in situ hybridization, comparative genomic hybridization, array comparative genomic hybridization, and by virtual karyotyping with SNP arrays. Recent advances in DNA sequencing technology have further enabled the identification of CNVs by next-generation sequencing.

CNVs can be limited to a single gene or include a contiguous set of genes. CNVs can result in having either too many or too few of the dosage-sensitive genes, which may be responsible for a substantial amount of human phenotypic variability, complex behavioral traits and disease susceptibility.

In certain cases, such as rapidly growing Escherichia coli cells, the gene copy number can be 4-fold greater for genes located near the origin of DNA replication, rather than at the terminus of DNA replication. Elevating the gene copy number of a particular gene can increase the expression of the protein that it encodes.