DNA sequencing has brought many important improvements to medicine, and is a fieldof active development. Through the study of genetic information, we gain knowledgeof hereditary diseases and traits, both in humans and other species.However, the process of sequencing is difficult, both due to vast amounts of dataand sequencing errors. Verification of results is often done with expensive re-sequencingand analysis.In this thesis we study the use of simulated reads in order to obtain exact results.First we suggest a method for creating a known artificial genome, using dbSNP toprovide variation. Several existing programs for variant calling are evaluated throughdetailed analysis of variant files. Finally we suggest methods for improving verificationof results.The results show that the GATK variant callers performed well, but also Dindelprovided some advantages. Furthermore, results suggest that some issues are caused byerroneous mapping and realignment.We hope that others can use these results to improve the development of sequencingalgorithms through simulations.