Laws of inheritance with traits passed as distinct discrete entities between generations, with trait variation because inheritable factors (Mendel 1865)
Nucleic acids isolated (Miescher 1869)
'Gene' (from Greek 'genesis' or 'genos') used to describe determining factor in gamete for a characteritic (Johannsen 1909)
Linear model of genes on a chromosome ('beads on a string') (Morgan 1910) First genetic map (Sturtevant 1913)
Heredity recognised to have a physical basis
- Xrays lead to mutations (Muller 1927)
- transfer of virulence factor in Pneumococcus (Griffith 1928) destroyed by DNase (Avery 1944)
Mutations in genes cause metabolic defects (Beadle & Tatum 1941) Idea of 'one gene, one enzyme' and 'one gene one polypeptide'
DNA is genetic material (Hershey & Chase 1952)
Structure of DNA double helix (Watson & Crick 1953)
Information flow DNA to RNA to protein (Crick 1958)
RNA transcript deciphered using genetic code (Nirenberg 1961)
First sequence of a gene (COAT-BPMS2 from bacteriphage) (Fiers 1971,6)
Identification and definition of genes from DNA sequence characteristics
Introns and RNA splicing (Sharp & Roberts 1977)
First large scale gene function analysis in yeast (1994) Genescan computer progrms for gene structure determination (1997) Publication of draft human genome (Lander 2001, Venter 2001) Completion of ENCODE pilot project (2007)
Figure 1.3 Changing views of a 'gene'. A timeline highlighting evolving concepts of a gene is shown together with dates of key advances. An open reading frame (ORF) refers to a sequence of bases that could potentially encode a protein. Adapted with permission from Gerstein et al. (2007).
Figure 1.4 Peripheral blood smear from a patient with sickle cell disease. Sickle-shaped red blood cells are shown (indicated by arrows) together with misshaped cells (arrowheads). Reprinted with permission from Frenette and Atweh (2007).
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