Early Studies of Evolution and Genetics and the Future

Watson and Crick displaying their 3-dimensional concept of the structure of DNA

In the history of science, three reports represent seminal contributions to understanding human nature:

(i) The Origin of Species by Natural Selection in 1859, the result of the observations of Charles Robert Darwin (1809-1882) during his five years (1831 to 1836) voyage on HMS Beagle.

(ii) The monograph by Gregor Johann Mendel (1822–1884), Versuche über Pflanzen-Hybriden (Experiments in Plant Hybridization) published in 1866 in the Transactions of the Natural History Society of Brünn, Moravia in the Austro-Hungarian Empire.

(iii) The description of the structure of DNA by James Dewey Watson (b.1928) and Francis Harry Compton Crick (1916-2004) published in the journal Nature in April 1953. (Figure)

Genetics as a discipline began to flourish at the turn of the twentieth century. Hugo Marie de Vries a Dutch botanist introduced the term “pangene” to indicate the fundamental unit of heredity and the concept of mutations as the path to speciation in the late 19th century. Danish botanist Wilhelm Johannsen converted the term to “gene” in 1909. Thomas Hunt Morgan, then at the newly formed California Institute of Technology (formerly Throop University), concluded that genes were arranged in a linear fashion on chromosomes. The term “chromosome” derives from the fact that these structures were conspicuously stained with dye (“chroma” means colored in Greek). Morgan won the first Nobel Prize in Physiology or Medicine awarded for genetic studies in 1933. His award was delayed several years until the Nobel Foundation was convinced that genetic studies in the fruit fly were relevant to medicine. [See Musing, “The Profound Impact of Drosophila Melanogaster, the Fruit Fly, and Danio Rerio, the Zebrafish, on Understanding the Human Genome and its Role in Disease.”]

The scientific community had ignored for three decades the implications of the profound discoveries by Gregor Johann Mendel, an Augustine monk and technical high school teacher, in the mid-nineteenth century. One explanation given for Mendel‘s obscurity was the effect of Darwin‘s treatise in 1859 and the dominance that the topic of evolution and natural selection had in scientific discourse over the ensuing years. More likely were: (i) the minimal distribution of Mendel‘s findings and conclusions, (ii) his failure to continue his research after he was elevated to Abbot at the Altbrünn monastery and (iii) the failure of his colleagues in botany (and beyond) to recognize the significance of his work.

The ascension of genetics in the first years of the twentieth century was propelled by the rediscovery of Mendel‘s findings, virtually simultaneously, by two scientists in 1900: Hugo Marie De Vries (1848–1935) in Holland and Carl Correns (1864–1933) in Germany. They each published results that coincided with Mendel‘s findings and deductions and in the process of searching the literature found Mendel‘s report to which they gave scientific priority. They confirmed Mendel‘s insights, based on his experiments with the garden pea plant, that units of information in parents account for observable traits in offspring and are passed from one generation to the next in a predictable manner. Mendel found that inherited factors do not blend; they are transmitted intact. Each member of the parental generation transmits half of its hereditary factors to each offspring. Different offspring of the same parents, however, may receive different combinations of hereditary factors in predictable ratios. Certain factors are dominant, explaining their more frequent expression in the offspring. His two lectures on plant hybridization to the Natural History Society of Brünn, Moravia in the Austro-Hungarian Empire in February and March 1865 and the ensuing monograph described his most important findings. After three decades, his treatise, rediscovered, was distributed widely. The Royal Horticultural Society translated it into English in 1901. Today, Mendelian Genetics is a central thesis of our understanding of inheritance. The Online Mendelian Inheritance in Man (OMIM) database, maintained at Johns Hopkins University, is a continuously updated catalog of human genes and genetic disorders. Approximately 9,000 of the over 25,000 entries in OMIM represent genetic disorders or traits; the rest represent genes, many of which determine those disorders. Genome sequencing is revolutionizing biomedical discovery. It is projected that bioscience organizations will generate an exabyte, which is one quintillion (1,000,000,000,000,000,000) bytes of genetic data per year by 2025. Artificial intelligence (AI) is required to explore, interpret and apply this database for individual health and medical diagnosis.