Gene
Whatever is passed from parent to offspring and settles a hereditary trait. When Wilhelm Johannsen coined the word Gen in 1909, it was a name with nothing known behind it.
In his 1866 paper Mendel called the something that passes from parent to offspring an "element" (Element), and supposed that in a hybrid the differing elements separate when egg cells and pollen are formed. He said nothing about what an element was made of or where in the cell it might be[1].
In 1909 the Danish botanist Wilhelm Johannsen gave it a name: Gen, taken from the last syllable of "pangene", a word from Darwin's theory of heredity. Johannsen stressed that the word was completely free of any hypothesis, and wrote that no particular idea about the nature of genes was yet well enough founded[2].
One of Mendel's traits was finally traced more than eighty years later. In 1990 the wrinkled pea seed was shown to be caused by a piece of DNA inserted into the gene for an enzyme that puts branches into starch[3]. Mendel's "element" turned out to be a stretch of DNA.
Related terms
- Law of segregationThe rule that the two differing hereditary elements in a hybrid separate when egg cells and pollen are formed, so that each receives one or the other. Mendel set it out in 1866; it was rediscovered in 1900.
- Dominant and recessiveIn a hybrid, the form of a trait that shows is called dominant and the one that stays hidden is called recessive. The terms are Mendel's own: dominirend and recessiv.
Sources
- G. Mendel, “Versuche über Pflanzen-Hybriden,” Verhandlungen des naturforschenden Vereines in Brünn 4, Abhandlungen 3–47 (1866).
- W. Johannsen, “Elemente der exakten Erblichkeitslehre, pp. 124–125,” Jena: Gustav Fischer (1909).
- M. K. Bhattacharyya, A. M. Smith, T. H. N. Ellis, C. Hedley, C. Martin, “The wrinkled-seed character of pea described by Mendel is caused by a transposon-like insertion in a gene encoding starch-branching enzyme,” Cell 60(1), 115–122 (1990).