Abstract
BACKGROUND: The kinship2 package is restructured from the previous kinship package. Existing features are now enhanced and new features added for handling pedigree objects. METHODS: Pedigree plotting features have been updated to display features on complex pedigrees while adhering to pedigree plotting standards. Kinship matrices can now be calculated for the X chromosome. Other methods have been added to subset and trim pedigrees while maintaining the pedigree structure. CONCLUSION: We make the kinship2 package available for R on the Contributed R Archives Network (CRAN), where data management is built-in and other packages can use the pedigree object.