Computational Biology Group, Illumina Cambridge Ltd., Chesterford Research Park, Little Chesterford, Essex, UK. acox@illumina.com|Computational Biology Group, Illumina Cambridge Ltd., Chesterford Research Park, Little Chesterford, Essex, UK. acox@illumina.com|Computational Biology Group, Illumina Cambridge Ltd., Chesterford Research Park, Little Chesterford, Essex, UK. acox@illumina.com|Computational Biology Group, Illumina Cambridge Ltd., Chesterford Research Park, Little Chesterford, Essex, UK. acox@illumina.com