History of Genetics

By Dr Ananya Mandal, MD

Genomics involves the study of genes, genetics, inheritance, molecular biology, biochemistry, biological statistics and incorporates the knowledge of advanced technology, computer science and mathematics.

Mid to Late 19th Century

The origins of genetics lie in the development of theories of evolution. It was in 1858 that the origin of species and how species variability was developed after the research work of Charles Darwin and Wallace. They described how new species arose via evolution and how natural selection occurred to evolve new forms. They however did not know the role genes had to play in this phenomenon.

Around the same time Gregor Mendel, an Austrian monk, was performing extensive experiments on inheritance and genetics of sweet pea plants. He described the unit of heredity as a particle that does not change and is passed on to offspring. His work is in fact the basis of understanding the principles of genetics even today. Consequently, Gregor Mendel is known as the Father of Genetics. There was, however, little awareness of Gregor’s work during this time.

Also in this period Haeckel correctly predicted that the heredity material was located in the nucleus. Miescher showed the material in the nucleus was a nucleic acid. Chromosomes as units carrying genetic information was also discovered around this time.

Early 20th Century

It was during this time that the Mendelian Principles and the Chromosomal Theory of Inheritance was established. Mendel’s work was largely unknown. It was not until 1900 that there was a rediscovery of the Mendelian principles and publications began citing his work.

Development of the chromosomal theory led to advent of the field of cytogenetics. The first observations of chromosomal abnormalities (e.g. duplications, deletions, translocations, inversions) were reported around this time.

Mid 20th Century

It was in 1870s that the material in the nucleus was determined to be a nucleic acid. DNA was determined to be the genetic material between 1920s and mid-1950s. Griffith’s experiments with a bacterial strain established the theory.

Avery, MacLeod and McCarty further showed that DNA, not protein or RNA was the factor responsible for genetic inheritance and evolution of the bacterial strains studied by Griffith.

It was then that Watson and Crick in their groundbreaking work determined the structure of DNA, and others suggested that DNA contained a genetic code.  The code was discovered in the 1960’s. Crick discovered the process of transcription and translation and led to formation of the “central dogma of molecular biology”.

Mid-late 20th Century and the Early 21st Century

This period heralded the concept of molecular biology and molecular genetics. Various advanced technologies made their way into knowledge base around this time. This included molecular biology, recombinant DNA technology, and biotechnology methods.

Methods of radiolabelling of the DNA with radioactive or fluorescent tags for development of diagnostic and therapeutic methods as well as research tools were discovered during this time.

Restriction enzymes were discovered and used to construct recombinant DNA molecules that contained foreign DNA that could be grown in abundance in bacterial strains.

Then came methods like PCR (Polymerase chain reaction) and host of other biotechnology methods and new applications were found in medicine, pharmacotherapeutics as well as research.

Mid to Late 19th Century: Evolution, Natural Selection, Particulate Inheritance and Nuclein 1858

  • Darwin and Wallace - Role of natural variation and natural selection in evolution
  • 1865 -  Gregor Mendel - Particulate inheritance
  • 1866 - Ernst Haeckel;  Heredity materials was in the nucleus
  • 1871 -  Friedrich Miescher;  Material in the nucleus was a nucleic acid

Early 20th Century: Mendelian Principles are extended and the Chromosomal Theory of Inheritance solidifies

  • 1900 - Correns, de Vries, von Tschermak - Mendel’s work is rediscovered;The age of genetics begins
  • 1902 - Walter Sutton and Theodor Boveri - Chromosomal Theory of Inheritance; The heredity material resides in chromosomes
  • 1905-1923
    • Linkage
    • Sex linkage
    • Genetic mapping
    • Number of linkage groups - number of chromosomes
    • Lethal genes
    • Maternal inheritance
  • 1908 - Hardy and Weinberg - Hardy-Weinberg principle of genetic equilibrium
  • 1909 - Nilsson-Ehle - Theory of quantitative traits and quantitative genetics

Mid 20th Century: DNA is the stuff of life; the preeminence of the Darwinian theory of evolution via natural selection is confirmed

  • 1928 - Griffith - Transformation experiments
  • 1944 - Avery, MacLeod, McCarty - Definitive proof that DNA is the genetic material
  • 1953 - Watson and Crick - DNA structure is defined
  • 1954-1961
    • DNA code is determined
    • Transcription is described
    • Replication is described
    • Translation is described
    • Operons are discovered
  • 1932-1953
    • Fisher and Dobzhansky - The Modern Synthesis is formulated
    • Links Darwinian evolutionary theory and Mendelian genetics
  • 1968
    • Kimura
    • Neutral Theory of Molecular Evolution is introduced

Mid-late 20th  Century and the Early 21st Century: The Age of Molecular Genetics; Phylogenetics Studies Intensive; The Information Age; The Emergence of Genomics Science

  • 1969 - ARPANET - Internet comes on line
  • 1970 - Arber and Smith - First restriction enzyme, Hind II, is isolated
  • 1970 - Baltimore and Temin - Discovery of reverse transcriptase
  • 1972 - Berg - First recombinant DNA molecule is constructed
  • 1973 - Boyer and Cohen - First functional recombinant E. coli cell produced
  • 1977 - Sanger and Gilbert - DNA sequencing techniques are described
  • 1977 - Sharp and Roberts - Introns discovered
  • 1978 - Botstein - RFLPs launch the era of molecular mapping of linkage groups
  • 1980 - Sanger Group - First genome is sequenced, the bacteriophage ΦX174 of E. coli
  • 1983 - Mullis - PCR technique is discovered
  • 1986 - Hood, Smith, Hunkapiller and Hunkapiller - First automated DNA sequencer
  • 1990 - US Government - Human Genome Project launched
  • 1995 - Celera - First bacterial genome (H. influenza) is sequenced
  • 1996
    • Yeast Genome Consortium
    • First eukaryotic genome (yeast) sequenced 
  • 2000 - Arabidopsis Genome Initiative - First flowering plant genome (Arabidopsis thaliana) is  sequenced
  • 2001 - The human genome sequence is published

Reviewed by , BA Hons (Cantab)

Further Reading

 

Last Updated: Jan 1, 2013

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