Karen Nelson is a Jamaican-born American microbiologist (specializing in human microbiome research) who was formerly president of the J. Craig Venter Institute (JCVI).

[2] Nelson is a prominent expert in microbial genomics and metagenomics, with applications to human health.

[8] Nelson was appointed president of JCVI in 2012 after serving as the director of its Rockville Campus since 2010.

[9] Prior to being appointed President, she held a number of other positions at the Institute, including Director of JCVI's Rockville Campus, and Director of Human Microbiology and Metagenomics in the Department of Human Genomic Medicine at JCVI.

[2] She has authored or co-authored over 200 peer reviewed publications, edited three books, and is currently Editor-in-Chief of the journal Microbial Ecology and the newly announced PNAS Nexus.