Inheritance of Acquired Characteristics - History

History

The idea was proposed in ancient times by Hippocrates and Aristotle, and was commonly accepted near to Lamarck's time. Lamarck published his theory in 1809, the year Darwin was born. He noticed several lines of descent by comparing current species with fossil forms. He noticed that the older the fossils were, the more alike they were to modern species. Two ideas were incorporated in Lamarck’s theory. The first was the theory of use and disuse; the idea that body parts used more often become stronger and larger, while parts not used slowly waste away and disappear. The second idea was the inheritance of acquired characteristics theory, the concept that modifications that occur during an organism's lifetime are passed on to its offspring. His example was the giraffe. He believed that the long neck of the giraffe resulted from the ancestors of giraffes stretching their necks longer and longer while trying to reach the highest branches of the trees. Comte de Buffon, before Lamarck, proposed ideas about evolution involving the concept, and even Charles Darwin, after Lamarck, developed his own theory of inheritance of acquired characters, pangenesis. The basic concept of inheritance of acquired characters was finally widely rejected in the early 20th century.

In the 1920s, Harvard University researcher William McDougall studied the abilities of rats to correctly solve mazes. His reports claimed that offspring of rats that had learned the maze were able to run it faster. In his data, the first rats would get it wrong 165 times before being able to run it perfectly each time, but after a few generations, it was down to 20. McDougall attributed this to some sort of Lamarckian evolutionary process. However McDougall's results have never been replicated by other experimenters, and have been criticised for having several methodological problems and poor record-keeping.

During the rule of Joseph Stalin in the USSR in the 1930s, the theory of inheritance of acquired characteristics was central to the dogma put forth by Trofim Lysenko, president of the Soviet Academy of Agricultural Sciences. Lysenkoism was advanced primarily in service to Soviet agriculture, always resulting in dismal failure.

Recently, researchers have reexamined this concept in light of discoveries in epigenetics and transgenerational epigenetics. In some cases, experiences of parents or even grandparents have been found to cause differences in gene expressions.