Individual genomes vary, not only in sequence, but in both their structural organization and in the number of sequence copies they contain. The technology now exists to understand the mechanisms by which genomes diverge, so we can investigate the consequences of copy number variation for gene expression and clinical phenotypes. This month (September), Nature Genetics presents a Focus of articles published in Nature and Nature Genetics, free to read online, on copy number variation, which highlights the complementary roles of paired-end sequencing and oligonucleotide array technology in research discovery.

As well as an Editorial (‘Making diversity count’) and an NPG library of relevant past articles, the Focus consists of the following research articles:

A highly annotated whole-genome sequence of a Korean individual

Jong-Il Kim et al.

The DNA replication FoSTeS/MMBIR mechanism can generate genomic, genic and exonic complex rearrangements in humans

Feng Zhang et al.

Increased LIS1 expression affects human and mouse brain development

Weimin Bi et al.

Mapping and sequencing of structural variation from eight human genomes

Jeffrey M Kidd et al.

Closing gaps in the human genome with fosmid resources generated from multiple individuals

Donald Bovee et al.