Sunday, October 14, 2018

Gregor Mendel and genetics


Photo source: Wikimedia Commons

Gregor Mendel (1822-1884) was a German biologist best known for his pioneering work on genetics. Biologist David P. Clark said,
"The birth of modern genetics was due to the discoveries of Gregor Mendel (1823-1884), an Augustinian monk who taught natural science to high school students in the town of Brno in Moravia. Mendel's greatest insight was to focus on discrete, clear-cut characters rather than measuring continuously variable properties, such as height or weight. Mendel used pea plants and studied characteristics such as whether the seeds were smooth or wrinkled, whether the flowers were red or white, and whether the pods were yellow or green, etc." (Molecular Biology, 2010)
The rest of this post is some quotes from Mendel.

Traits


"That no generally applicable law of the formulation and development of hybrids has yet been successfully formulated can hardly astonish anyone who is acquainted with the extent of the task and who can appreciate the difficulties with which experiments of this kind have to contend." (Experiments in plant-hybridisation, 1865)

"The striking regularity with which the same hybrid forms always reappeared whenever fertilisation took place between the same species induced further experiments to be undertaken..." (Experiments in plant-hybridisation, 1865)

"Experiments on ornamental plants undertaken in previous years had proven that, as a rule, hybrids do not represent the form exactly intermediate between the parental strains." (Experiments in plant-hybridisation, 1865)

"The course of development consists simply in this; that in each generation the two parental traits appear, separated and unchanged, and there is nothing to indicate that one of them has either inherited or taken over anything from the other." (Letter to Carl Nageli, 1867)

"In this generation, along with the dominating traits, the recessive ones also reappear, their individuality fully revealed, and they do so in the decisively expressed average proportion of 3:1, so that among each four plants of this generation three the dominating and one the recessive characteristic." (Experiments in plant-hybridisation, 1865)