Figure 1.1 A brief history of genetics 1865 Genes are particulate factors 1903 Chromosomes are hereditary units 1910 Genes lie on chromosomes 1913 Chromosomes contain linear arrays of genes 1927 Mutations are physical changes in genes 1931 Recombination is caused by crossing over 1944 DNA is the genetic material 1945 A gene codes for a protein 1953 DNA is a double helix 1958 DNA replicates semiconservatively 1961 Genetic code is triplet 1977 DNA can be seq nced 1997 Genomes can be sequenced 目录目 录