Genetics

Genetics is the branch of biology that studies heredity. The passing of biological information from parents to offspring occurs through the combination of genes that are unique to each individual person, animal or plant that reproduces through living cells. As a field of study, it is concerned with the origin of individual characteristics and the way that these are transmitted to offspring. Genetics has developed over the centuries from the view of Aristotle and others that the species are fixed. One ancient idea being that inside of the seed of a man was another tiny little man. Inside of his seed was another tiny little man and so on through the generations.

Charles Darwin's ideas on evolution sparked controversy in part over how it was possible for species to develop into different animals from “lesser” species. The prevailing view in his time was that of Jean-Bap-tiste Lamarck (1744–1829) who had viewed heredity as proceeding according to natural laws, in particular through “acquired characteristics.” His theory which was also accepted by Darwin and by others until the discovery of the ideas of Gregor Johann Mendel (1822–84) was recognized at the beginning of the 20th century.

A particularly notorious result of the Lamarckian understanding of Darwinism occurred from its adoption into social and political ideas. Herbert Spencer adopted the idea of evolution directed by the acquired characteristics of human beings to his socioeconomic theory. Followers like William Graham Sumner brought his ideas to America where they were used with a moral component added to justify the capitalism of the Robber Barons and others in the late 19th century. The Supreme Court also incorporated the idea into its rulings. The effect of Social Darwinism was to say that the successful (the rich) are the evolutionarily advanced and the poor are those that should be left to die because society will be better for it. Other political theories also adopted this view. The rediscovery in 1900 of a paper published by Gregor Mendel, an Augustinian monk from Moravia set modern genetics on the path of genes as the bearers of inheritance.

Mendel's work as a gardener revealed to him that pea plants inherited traits. The traits came from the parents to the offspring. Having practiced gardening in his youth between 1850 and 1863 he grew and test over 29,000 pea plants (Pisum sativum). He observed that all traits were not inherited by the offspring, just some of the traits of each parent. He was able to show the genetic inheritance of the pea strains. One in four of the pea plants had pure bred recessive alleles. Two out of four were hybrids and one out of four was the dominant purebred type. He show that the inheritance of traits followed laws. These laws have since become known as Mendel's Laws of Inheritance. He published his theory (“Experiments on Plant Hybridization”) in an obscure journal in 1866 (Proceedings of the Natural History Society of Brunn) in Brunn, Moravia (now Brno, Moravia). His theory was ignored until 1900 when the importance of his work was recognized. His paper was republished in a journal with an international readership.

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