GENOMICS NUCLEOTIDE SEQUENCES AND RECOMBINANT DNA

Generic Recombination, made possible by the discovery of the recombinant DNA procedure in the 1970s, makes it possible to develop extensive and detailed maps of the nucleotide sequences of gene molecules—to the point where, in 1990. plans were outlined for mapping the complete human genome, a program that wax well underway as of 1994. 

Figure 4 Nucleotide sequence (3940-bp) of genomic DNA of Nostoc sp. strain PCC 73102 containing hupS and hupL. Conserved cysteines are boxed, and the potential recombination site is underlined. GenBank accession no. AF030525 (Oxelfelt et al., 1998).

Chloroplasts of land plants contain multiple identical circular double-stranded DNA molecules, whose size, according to different data, varies from 120 to 160 or to 220 kb. In the population of cpDNA molecules obtained by chloropiast lysis, monomeric circles prevail (-60% of all circular DNA molecules in tobacco). There also ate oligomeric forms, which are concatemers or head-to-tail associates that most probably arose during DNA recombination and/or replication, as well as atypical molecules, presumably replicative intermediates. Accordingly, the chloropiast genome is not uniform and exists in the cell as a DNA population heterogeneous in molecule size and conformation. The first complete nucleotide sequences of cpDNA were determined in 1986 for tobacco ... 

---