AGB 121: Principles of Animal Genetics and Population Genetics (2+1)

GENE CONCEPT

• “Gene” is a theoretical term. Like all theoretical terms, its meaning has dramatically changed over and over in time, and it has been defined in so many different operational ways.
• Firstly it shows that the theoretical concepts of classical genetics cannot be correlated unambiguously with the theoretical concepts of molecular genetics.
• It was only in the nineteenth century that heredity became a major problem to be dealt with in biology.
• In the second half of the nineteenth century, Carl Naegeli and August Weismann distinguished the body substance, the “trophoplasm” or “soma”, from a specific hereditary substance, the “idioplasm” or “germ plasm”, which was assumed to be responsible for intergenerational hereditary continuity.
• Charles Darwin called the presumed hereditary particles as “gemmules”; Hugo de Vries, “pangenes”.