The relationship between genes and DNA: There are many genes on each DNA, and genes are DNA fragments with genetic effects. DNA is one of the four biological macromolecules contained in biological cells, a type of nucleic acid. DNA carries the genetic information necessary for the synthesis of RNA and proteins, and is an essential biological macromolecule for the development and normal operation of organisms.

The concept of early genes was only a deduction made based on the genetic phenomenon of biological traits, and did not refer to a certain substance. Morgan et al. concluded based on genetic evidence (fruit fly hybridization experiments and other scientists' hybridization experiments) and cytological observations that genes exist in linear order on chromosomes, while their relative positions remain unchanged.