Science Fair Project Encyclopedia
History of genetics
Pre-Mendelian ideas on heredity
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.
- 1859 Charles Darwin publishes The Origin of Species
- 1865 Gregor Mendel's paper, Experiments on Plant Hybridization
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
- 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 Ronald Fisher publishes On the correlation between relatives on the supposition of Mendelian inheritance - the modern synthesis of genetics and evolutionary biologystarts. See population genetics.
- 1927 Physical changes in genes are called mutations
- 1928 Frederick Griffith discovers a hereditary molecule that is transmissible between bacteria (see Griffiths experiment)
- 1931 Crossing over is the cause of recombination
- 1941 Edward Lawrie Tatum and George Wells Beadle show that genes code for proteins; see the original central dogma of genetics
The DNA era
- 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
- 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
The genomics era
See genomics, history of genomics
- 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; .
- 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 
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