In 1999, Dr. Gunaratne joined the International Human Genome Project, contributing to the sequencing and annotation of Human Chromosomes 3, 12, and X. In 2000, she became Director of gene (cDNA) sequencing at the Baylor Human Genome Sequencing Center. In 2006, she joined the University of Houston and established a functional genomics platform to identify genetic signatures that predict genome responses to microRNAs and drugs. Collaborating with teams from Baylor College of Medicine and MD Anderson, she pioneered methods for discovering tumor suppressor microRNAs for various cancers. Her work also defined microRNA-regulated gene signatures for personalized cancer treatments.