ABSTRACT
Sequencing of deoxyribonucleic acid began to be performed in laboratories in 1978. During the same period, in 1986, Japanese scientists surprised the international community by sequencing a whole series of chloroplast genomes, using only manual apparatus. The presequencing mapping, which will be presented here, requires a rather high level of coverage between neighboring Bacterial Artificial Chromosomes (BAC), which necessitates the construction of BAC libraries of about 25 genome equivalents. In August 1996, the Arabidopsis Genome Initiative was created; it included public or nonprofit laboratories from the United States, Europe and Japan. The sequencing of rice had already begun to be seriously envisaged even before the sequencing of A. thaliana was finished. Maize is certainly the largest “graveyard” of retrotransposons which constitute between 65 and 70% of its genome. The scientific community became rapidly focused on Medicago truncatula, which is a diploid ancestor of the tetraploid cultivated alfalfa.
