Robert Lee Metzenberg (June 11, 1930 – July 15, 2007) was an American geneticist known for his work on genetic regulation and metabolism with Neurospora crassa.
In 1951 Metzenberg graduated from Pomona College in California where he had specialised in chemistry with physics and biology as minor subjects.
During this time he met and was influenced by several geneticists including George Beadle, Alfred Sturtevant, Herschel K. Mitchell and Max Delbrück.
Metzenberg and his collaborators studied sulphur and phosphate assimilation, uncovering the complex genetic control of these pathways.
They also created the first molecular map of the Nurospora genome, making use of the dispersed 5S rRNA genes and technology that was an early independent implement of RFLP analysis.
[2] From the mid-1990s he also uncovered a novel gene-silencing mechanism, meiotic silencing of unpaired DNA (MSUD), that was related to RNAi and explained many previously unexplained aberrations in meiosis in Neurospora and other fungi.