The spirochaete, transmitted by ticks, that causes Lyme disease in humans. Genome sequencing has revealed that the bacterium contains a 910,725 bp megachromosome and 17 different plasmids with a combined size of 533,000 bp. The main chromosome contains about 850 genes, and there are at least 430 genes on the plasmids. Unlike the chromosomes of most bacteria which are circular, the main chromosome and some of the plasmids are linear. The DNA in the telomeres (q.v.) forms covalently closed hairpin structures. See Classification, Prokaryotes, Bacteria, Spirochaetae; Chronology, 1997, Fraser et al.
Subjects: Genetics and Genomics.