History of genetics

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Gregor Mendel, the "father of genetics"
Gregor Mendel, the "father of genetics"

The history of genetics is generally held to have started in 1865 when an Austrian monk, Gregor Mendel published his work on pea plants.

Contents

[edit] Pre-Mendelian ideas on heredity

See heredity

[edit] Mendel

In 1865 an Austrian monk Gregor Mendel first traced inheritance patterns of certain traits in pea plants and showed that they obeyed simple statistical rules. Although not all features show these patterns of Mendelian inheritance, his work acted as a proof that application of statistics to inheritance could be highly useful. Since that time many more complex forms of inheritance have been demonstrated.

From his statistical analysis Mendel defined a concept that he described as an allele, which was the fundamental unit of heredity. The term allele as Mendel used it is nearly synonymous with the term gene, whilst the term allele now means a specific variant of a particular gene.


1865 Gregor Mendel's paper, Experiments on Plant Hybridization

[edit] Post-Mendel, pre-re-discovery

Mendel's work was published in a relatively obscure scientific journal, and it was not given any attention in the scientific community. Instead, discussions about modes of heredity were galvanized by Darwin's theory of evolution by natural selection, in which mechanisms of non-Lamarckian heredity seemed to be required. Darwin's own theory of heredity, pangenesis, did not meet with any large degree of acceptance. A more mathematical version of pangenesis, one which dropped much of Darwin's Lamarckian holdovers, was developed as the "biometrical" school of heredity by Darwin's cousin, Francis Galton. Under Galton and his successor Karl Pearson, the biometrical school attempted to build statistical models for heredity and evolution, with some limited but real success, though the exact methods of heredity were unknown and largely unquestioned.

[edit] Classical genetics

The significance of Mendel's work was not understood until early in the twentieth century, after his death, when his research was re-discovered by other scientists working on similar problems. Hugo de Vries, Carl Correns and Erich von Tschermak

There was then a feud between Bateson and Pearson over the hereditary mechanism. Fisher solved this in The Correlation Between Relatives on the Supposition of Mendelian Inheritance

1880-1890 Walther Flemming, Eduard Strasburger, and Edouard van Beneden elucidate chromosome distribution during cell division
1903 Chromosomes are discovered to be hereditary units
1905 British biologist William Bateson coins the term "genetics" in a letter to Adam Sedgwick
1908 Hardy-Weinberg law derived.
1910 Thomas Hunt Morgan shows that genes reside on chromosomes
1913 Alfred Sturtevant makes the first genetic map of a chromosome
1913 Gene maps show chromosomes containing linear arranged genes
1918 R.A. Fisher publishes On the correlation between relatives on the supposition of Mendelian inheritance - the modern synthesis of genetics and evolutionary biology starts. See population genetics.
1927 Physical changes in genes are called mutations
1928 Frederick Griffith discovers that hereditary material from dead bacteria can be incorporated into live bacteria (see Griffiths experiment)
1931 Crossing over is identified as the cause of recombination
1933 Jean Brachet is able to show that DNA is found in chromosomes and that RNA is present in the cytoplasm of all cells.
1941 Edward Lawrie Tatum and George Wells Beadle show that genes code for proteins; see the original central dogma of genetics

[edit] The DNA era

James Watson and colleagues discovered the structure of DNA
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James Watson and colleagues discovered the structure of DNA
1944 Oswald Theodore Avery, Colin McLeod and Maclyn McCarty isolate DNA as the genetic material (at that time called transforming principle)
1950 Erwin Chargaff shows that the four nucleotides are not present in nucleic acids in stable proportions, but that some general rules appear to hold (e.g., that the amount of adenine, A, tends to be equal to that of thymine, T). Barbara McClintock discovers transposons in maize
1952 The Hershey-Chase experiment proves the genetic information of phages (and all other organisms) to be DNA
1953 DNA structure is resolved to be a double helix by James D. Watson and Francis Crick[1]
1956 Jo Hin Tjio and Albert Levan established the correct chromosome number in humans to be 46
1958 The Meselson-Stahl experiment demonstrates that DNA is semiconservatively replicated
1961 The genetic code is arranged in triplets
1964 Howard Temin showed using RNA viruses that Watson's central dogma is not always true
1970 Restriction enzymes were discovered in studies of a bacterium, Haemophilius influenzae, enabling scientists to cut and paste DNA

[edit] The genomics era

See genomics, history of genomics

1972, Walter Fiers and his team at the Laboratory of Molecular Biology of the University of Ghent (Ghent, Belgium) were the first to determine the sequence of a gene: the gene for bacteriophage MS2 coat protein[2].
1976, Walter Fiers and his team determine the complete nucleotide-sequence of bacteriophage MS2-RNA[3]
1977 DNA is sequenced for the first time by Fred Sanger, Walter Gilbert, and Allan Maxam working independently. Sanger's lab complete the entire genome of sequence of Bacteriophage Φ-X174[4].
1983 Kary Banks Mullis discovers the polymerase chain reaction enabling the easy amplification of DNA
1989 The first human gene is sequenced by Francis Collins and Lap-Chee Tsui, it encodes the CFTR protein, defects in this gene cause cystic fibrosis
1995 The genome of Haemophilus influenzae is the first genome of a free living organism to be sequenced
1996 Saccharomyces cerevisiae is the first eukaryote genome sequence to be released
1998 The first genome sequnce for a multicellular eukaryote, C. elegans is released
2001 First draft sequences of the human genome are released simultaneously by the Human Genome Project and Celera Genomics.
2003 (14 April) Successful completion of Human Genome Project with 99% of the genome sequenced to a 99.99% accuracy [1]

[edit] See also

[edit] External links

[edit] Further reading

  • Elof Axel Carlson, Mendel's Legacy: The Origin of Classical Genetics (Cold Spring Harbor Laboratory Press, 2004.) ISBN 0-87969-675-3

[edit] References

  1. ^ Watson JD, Crick FH, Molecular structure of nucleic acids; a structure for deoxyribose nucleic acid, Nature. 1953 Apr 25;171(4356):737-8
  2. ^ Min Jou W, Haegeman G, Ysebaert M, Fiers W., Nucleotide sequence of the gene coding for the bacteriophage MS2 coat protein, Nature. 1972 May 12;237(5350):82-8
  3. ^ Fiers W et al., Complete nucleotide-sequence of bacteriophage MS2-RNA - primary and secondary structure of replicase gene, Nature, 260, 500-507, 1976
  4. ^ Sanger F, Air GM, Barrell BG, Brown NL, Coulson AR, Fiddes CA, Hutchison CA, Slocombe PM, Smith M., Nucleotide sequence of bacteriophage phi X174 DNA, Nature. 1977 Feb 24;265(5596):687-95
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