Ja·cob (zhä-kôb?), François 1920-2013. French geneticist. He shared a 1965 Nobel Prize for his research on the regulation of gene expression, including the role of messenger RNA.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.Ja·cob (zhä-kôb?), François Born 1920. French geneticist who studied how genes control cellular activity by directing the synthesis of proteins. With Jacques Monod, he theorized that there are genes that regulate the activity of other, neighboring genes. They also proposed the existence of messenger RNA.The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.