Reading in ?RangesMatching-class that 'To get the actual regions of intersection between the overlapping ranges, use the 'ranges' accessor' But in my possibly naive or mistaken use, it does not seem to work: range.1 = IRanges (start = c (10, 20), end = c (15, 23)) range.2 = IRanges (start = c (13, 19), end = c (18, 25)) overlap.12 = overlap (range.1, range.2) ranges (overlap.12) Error in is(query, "Ranges") : element 1 is empty; the part of the args list of 'class' being evaluated was: (object) Any advice? Thanks! - Paul sessionInfo () R version 2.9.0 (2009-04-17) x86_64-unknown-linux-gnu locale: LC_CTYPE = en_US .UTF -8 ;LC_NUMERIC = C ;LC_TIME = en_US .UTF -8 ;LC_COLLATE = en_US .UTF -8 ;LC_MONETARY = C ;LC_MESSAGES = en_US .UTF -8 ;LC_PAPER = en_US .UTF -8 ;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_US.UTF-8;LC_I \ DENTIFICATION=C attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] Biostrings_2.12.1 IRanges_1.2.2 RMySQL_0.7-4 DBI_0.2-4 RUnit_0.4.22 loaded via a namespace (and not attached): [1] Biobase_2.4.1 tools_2.9.0