suggests that the bacterium's second chromosome may have started life as a megaplasmid.
By William Wells(firstname.lastname@example.org) | August 7, 2000
In the 3 August Nature, The Institute for Genomic Research (TIGR) has unveiled its twentieth completed bacterial sequence (Heidelberg et al, Nature 2000, 406:477-484). The complete sequence of the cholera-causing bacterium Vibrio cholerae consists of the 2.96 Mbp chromosome 1 and the 1.07 Mbp chromosome 2. Chromosome 1 contains a standard bacterial origin of replication and the vast majority of the bacterium's essential genes, whereas chromosome 2 has an origin of replication and various genes that are usually associated with plasmids, and thus may have started life as a megaplasmid. The two chromosome have, however, coexisted for a long time based on their almost identical G+C content. Moreover, chromosome 2 now has several essential genes, and a number of regulatory proteins control genes on both chromosomes. The bacterium's strategies for coordinating replication and segregation of the two chromosomes remain to be established.
This year’s controversial news included unethical behavior among politicians, a murder, and multiple accusations of gender discrimination and sexual harassment, in addition to the usual spate of research misconduct.