OVERVIEW
GATK
GATK4 aims to bring together well-established tools from the GATK and Picard codebases under a streamlined framework, and to enable selected tools to be run in a massively parallel way on local clusters or in the cloud using Apache Spark. It also contains many newly developed tools not present in earlier releases of the toolkit.
GATK offcial site: https://gatk.broadinstitute.org/hc/en-us