With the sequencing of the human genome came the startling revelation that the number of copies of a given gene can vary widely between individuals. This Copy Number Variation (or CNV), contributes to our species’ genetic diversity but it has also been linked to genetic diseases. This month’s issue of Cold Spring Harbor Protocols features a new method for detecting copy number variation. Like all of our monthly featured protocols, it’s freely accessible for subscribers and non-subscribers alike.

Copy Number Variation Detection Via High-Density SNP Genotyping describes the use of PennCNV, a new computational tool for CNV detection in data from genomic arrays. Developed in the laboratory of Maja Bucan at the University of Pennsylvania, the software is freely available for download. Analysis with PennCNV will provide a more comprehensive understanding of genome variation and will aid in studies seeking the causes of genetic diseases. More information on PennCNV can be found in this Genome Research article, PennCNV: An integrated hidden Markov model designed for high-resolution copy number variation detection in whole-genome SNP genotyping data.