The present invention, SMASH (Short Multiply Aggregated Sequence Homologies), is a technique designed to pack multiple independent mappings into every read. Specifically, the invention relates to a composition comprising a first mixture of different chimeric genomic nucleic acid fragments, wherein each different fragment in the mixture comprises randomly ligated DNA segments, wherein each DNA segment in the fragment is a nucleic acid molecule at least 27 base pairs in length resulting from random fragmentation of a single genome. The invention also relates to methods for generating said composition and use of said composition to obtain genomic information, for example, copy number variation.