Introduction » up to 1900 » 1901 to 1953 » 1954 to 1982 » 1983 to 2008

This is a timeline of major events in the science of genomics: the science of DNA encoding and how genes work. Part 1 begins from Hooke’s observation of the cell in 1665 to the rediscovery of Mendel’s particulate theory of genetics in 1900, the beginning of the science of modern genetics, the science of heredity.

To 1859: Fundamentals of Cellular Biology

1665: British scientist and Issac Newton’s rival Robert Hook coins the term “cell” and publishes Micrographia.

The cell is the fundamental unit of life in which all virtually all life functions occur. Awareness of the cell is a prerequisite to the study of biochemistry, genetics, and genomics.

Poor Hooke will be probably forever known best as Newton’s rival for his competing work about gravity and light. Hooke is otherwise best remembered for Hooke’s Law of elasticity: <em>F = -kx</em>

1806: French chemist Louis-Nicolas Vauquelin isolates the first amino acid, asparagine.

Asparagine is one of 20 naturally occurring amino acids. Vauquelin himself is best known for discovering two elements in the course of his meticulous experimental career: beryllium and chromium.

1831: British botanist Robert Brown describes and names the nucleus in plant cells —a discovery which he humbly presented embedded in a pamphlet about orchid sexual organs.

In eukaryotic cells, the cells of multi-cellular life, the nucleus is an organelle which contains and copies the cell’s DNA —its genetic information.

Brown, like his peer Charles Darwin, was an appointed expeditionary naturalist on a sea voyage to Australia. Unlike Darwin, despite Brown’s discovery of about 1700 new plant species and 140 plant genera from around the world, Brown’s greatest achievements came not from his vast observations abroad but from the very small and near. While observing pollen under a microscope, Brown noticed that the grains seemed to dart about randomly. In 1905, Albert Einstein postulated that this “Brownian motion” was direct evidence of molecular action, thus supporting the atomic theory of matter.

1836: German biologist Theodor Schwann discovers the enzyme pepsin.

Enzymes are proteins which catalyze chemical reactions. Understanding enzymes is key in understanding biochemistry. Without enzymes, many chemical reactions in the body effectively can not occur.

Schwann’s success as a biologist was in part because Schwann did not believe the traditional vitalism theories (like humorism) of human biology: that life functions by non-chemical means.

Side note: Superstition versus Superstition?

1838: Dutch chemist Gerardus Johann Mulder first describes and names “proteins.” The name “protein” was proposed by Mulder’s then associate Swedish Chemist Jöns Jakob Berzelius from the Greek word πρώτα (”prota”) meaning “of primary importance.”

Berzelius was a prolific chemist and is considered to be a father of modern chemistry. In addition to inventing modern chemical notation, discovered the law of constant proportions, and identifying the elements silicon, selenium, thorium, cerium, lithium, and vanadium, Berzelius was also the first to make the distinction between organic and inorganic compounds.

1839: German botanist Matthias Schleiden and Theodor Schwann formulate the cell theory: the theory that that cell is the fundamental unit of life.

Cell theory states that for all living things, regardless of complexity or size:

• All living things are composed of cells.

• Cells are the basic unit of structure and function in living things.

• All cells are produced from other cells.

This theory isn’t quite complete if one considers viruses to be “living.”

1855: Polish-German embryologist and neurologist Robert Remak describes cell division.

Robert Remak was Jewish and thus was denied professional achievement throughout his life.

1857: Swiss anatomist and physiologist Rudolph Albert von Kölliker describes “sarcosomes” (”mitochondria“) in muscle cells.

The Mitochondrion is a cell organelle with its own genome independent of the cell’s nucleus

Kölliker is best known for his contributions to histology, particularly of the nervous system. His success can be attributed to in part his adoption of new microscopy including slide preparation and staining.

1858: German pathologist Rudolf Virchow states his famous aphorism “every cell comes from a cell” in his work Cellular Pathology as Based upon Physiological and Pathological History.

Virchow soundly ended the theory of spontaneous generation: that life could arise from non-living matter. In addition to his successful scientific career, Virchow was a liberal political and social activist and is considered a pioneer of social medicine.

1859 to 1900: The Chromosome

1859: British naturalist Charles Darwin publishes On the Origin of Species by Means of Natural Selection.

Darwin’s work launched the field of evolutionary biology, which crystallized the philosophic revolution that humans are entirely natural and may be understood by scientific means.

Note:

I am tempted to omit Darwin from this timeline to protest the ugly little peasant revolt seething today in Western consciousness, but that would be unfair to Darwin, who is blameless for his status as a figure of contemporary controversy.

1861: German anatomist Max Schultze describes the cell as consisting of protoplasm and a nucleus.

Before Schultze, the popular theory was that the cell wall / cell membrane was the functionally important part of the cell. Schultze claimed that (correctly) the protoplasm manifests the essential life functions of a cell.

1865: Augustinian priest and scientist Gregor Mendel publishes Experiments on Plant Hybridization which described the laws of genetic inheritance derived from years of studying genetic traits in pea plants.

The previous theory, pangenesis, suggested that each cell shed particles of inheritance called “gemmules” which collected in reproductive organs and which specified the traits of an organism in aggregate. That is, Gregor discovered that inheritance is particulate rather than blended, the contemporary belief. The following work until 1900 leads

It’s interesting to note that Gregor Mendel’s work (and Gregor Mendel himself) was largely ignored until it was “rediscovered” in 1900, 16 years after Mendel’s death.

1869: Swiss biochemist Johann Friedrich Miescher isolates and describes a substance in the nuclei of cells that he calls “nuclein” (DNA)

“Nuclein” was discovered by accident when Miescher tried to isolate the nuclei of white blood cells in pus. Nuclein was odd because of its elemental composition: phosphorus, nitrogen, and sulfur. Despite further research, Miescher did not discover that DNA was the genetic material of the cell.

1873: German cytologist Walther Flemming discovers “chromosomes,” observes mitosis and provides the modern interpretation of nuclear division in Cell Substance, Nucleus, and Cell Division.

Flemming was, unfortunately, unaware of Gregor Mendel’s work on heredity and so did not make the connection between his discovery of the “threadlike structures in the cell nucleus which split along their lengths into two identical halves. However, Flemming’s discovery of mitosis, the process by which the cell nucleus divides, is considered to be one of the most important discoveries in biology.

1875: German-Polish botanist Eduard Strasburger describes the process of cell division, mitosis, in On Cell Formation and Cell Division.

Effectively, Strasburger helped quickly spread the ideas of mitosis to his field of botany in which he was famous authority.

1877: German physiologist and chemist Ernst Felix Immanuel Hoppe-Seyler Hoppe-Seyler coins the term “biochemistry.”

Great minds seem to work together. Hoppe-Seyler was first an assistant to Rudolf Virchow (”every cell comes from a cell”) and later was an professor to Friedrich Miescher (discoverer of “nuclein” DNA).

1888: Pursuing the research of his colleague, German anatomist Walther Flemming, Heinrich Wilhelm Gottfried von Waldeyer-Hartz observes and names the chromosomes in the nucleus of a cell. The word “chromosome” come from the Greek words χρῶμα (chroma, color) and σῶμα (soma, body) because in the lab, chromosomes can be stained to be very dark with dye.

A chromosome is a unit of organized DNA. If DNA is a language, and a genome a complete “book” of DNA in an organism, then a chromosome would be like a chapter. Extending the “Book of DNA” metaphor, if the human genome was a book, it would have:

• over one billion letters, or base-pairs of DNA
• about 20,500 sentences, or genes
• 46 chapters in 23 pairs, or chromosomes
• would fit in every human cell nucleus
• is over 2 meters in length

Waldeyer-Hartz himself is best otherwise known as the founder of neuroscience.

1892: German embryologist Oscar Hertwig establishes cytology as a discipline of biology.

Hertwig’s most notable discovery was that sperm penetration egg cells in fertilization. Hertwig also published “The Origin of Organisms - a Refutation of Darwin’s Theory of Chance.”

1898: Dutch microbiologist and botanist Martinus Beijerinck establishes the field of virology by coining the term “virus” to describe a disease-producing microscopic agent that can pass through a bacteriological filter.

The discovery of the virus is important because it’s a self-replicating unit of genetic material that is not a cell. Beijerinck discovery of the virus was inspired by his experiment that cell-free filtrate from tobacco mosaic disease infected plants was still virulent.

1900: Hugo de Vries, Carl Correns, and Erich von Tschermak-Seysenegg independently and simultaneously rediscover Mendel’s finding on heredity, thus launching the modern science of genetics at the dawn of the 20th century.

Ironically, Mendel’s rather humble research conducted breeding pea plants was the key missing theory to unify the prestigious genetic scientific discoveries of the late 19th century: the discovery of DNA, chromosomes, and mitosis and the establishments of the scientific fields of cytology and biochemistry.

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