Daniel Lee Nickrent is an American botanist, working in plant evolutionary biology, including the subdisciplines of genomics, phylogenetics, systematics, population genetics, and taxonomy.

[6] He is Research Faculty and Professor Emeritus of Plant Molecular Systematics and Evolution at Southern Illinois University Carbondale (SIUC) (As of July 2019[update]).

[10][11] During this period, his laboratory methodology changed from working with rRNA to DNA using the polymerase chain reaction (PCR) which made sequencing genes easier.

This resulted in the discovery of increased rates of gene evolution in parasitic plants[12] and the publication of one of the earliest species-level molecular phylogenies using nuclear ITS[13] on the dwarf mistletoes, Arceuthobium.

[11][10] His work on Rafflesia in the Philippines was supported by a grant from the National Geographic Society in 2008,[15] the start of a continuing collaboration with Julie Barcelona and Pieter Pelser.