A principle aim of the CCV is to make the ability to edit sequences in the human genome so precise and efficient that it will become routine for researchers to determine by direct experimentation exactly what sequences contribute to human cell phenotypes. Since the completion of the Human Genome Project, our knowledge of the genetic causes of human disease has come mainly from thousands of Genome Wide Association Studies (GWAS). GWAS can narrow down the locations of disease-associated genetic variations to particular regions of the human genome, but they cannot identify among potentially many DNA variations in a region are actually causative. More recently, by virtue of more comprehensively revealing DNA variation, researchers have found that by sequencing entire human genomes of disease-affected individuals and their close relatives (e.g., PubMed), or by sequencing only the protein coding fractions of their genomes (PubMed), they can identify disease-associated genome locations with single base precision. But these methods, although an advance over GWAS, also cannot prove that these positions are directly causative. By improving the ability of researchers to precisely manipulate human sequences, the methods developed by the CCV will fill these gaps and make possible high-throughput assays for the causative impact of natual variations and, ultimately, high-throughput reverse genetic approaches to understanding human cell phenoypes. The CCV works mainly with well-characterized human cell lines available from the Personal Genome Project, including human induced Pluripotent Stem Cells, with which we can explore the impact of casuative variations in different human tissue types. As additional aims, the CCV also develops high-throughput methods for in situ analysis of the expression of large numbers of genes in single human cells, and general technology for highly parallel generation of many large DNA constructs. CCV’s development of methods of efficiently engineering human cells of many cell types to contain designed sequences, and of analyzing individual human cells, will eventually have direct application to disease detection and gene therapy.