Science, Tech, Math › Science Gene Theory Share Flipboard Email Print Science Biology Genetics Basics Cell Biology Organisms Anatomy Physiology Botany Ecology Chemistry Physics Geology Astronomy Weather & Climate By Regina Bailey Biology Expert B.A., Biology, Emory University A.S., Nursing, Chattahoochee Technical College Regina Bailey is a board-certified registered nurse, science writer and educator. Her work has been featured in "Kaplan AP Biology" and "The Internet for Cellular and Molecular Biologists." our editorial process Regina Bailey Updated March 06, 2017 Definition: The Gene Theory is one of the basic principles of biology. The main concept of this theory is that traits are passed from parents to offspring through gene transmission. Genes are located on chromosomes and consist of DNA. They are passed from parent to offspring through reproduction.The principles that govern heredity were introduced by a monk named Gregor Mendel in the 1860's. These principles are now called Mendel's law of segregation and law of independent assortment.