01609nas a2200277   4500000000100000008004100001260001300042653001200055653001800067653002300085653001900108653002500127653001100152653002300163653004800186653002500234653003100259653001400290653002800304100001800332245009100350300000900441490000700450520086000457022001401317       1999                            d  c1999 Feb10aAnimals10aBase Sequence10aConserved Sequence10aDNA, Bacterial10aEvolution, Molecular10aHumans10aModels, Biological10aMycobacterium avium subsp. paratuberculosis10aMycobacterium leprae10aMycobacterium tuberculosis10aPhylogeny10aTandem Repeat Sequences1 aFrothingham R00aEvolutionary bottlenecks in the agents of tuberculosis, leprosy, and paratuberculosis.  a95-90 v523 a<p>Parasitic mycobacteria cause important human and animal diseases including tuberculosis, leprosy, and paratuberculosis. Several methods demonstrate a high degree of sequence conservation in three parasitic mycobacterial species (Mycobacterium tuberculosis, M. leprae, and M. avium subspecies paratuberculosis). Each of these species has completely conserved deoxyribonucleic acid (DNA) sequence in an internal transcribed spacer. In contrast, several species of environmental mycobacteria (M. intracellulare, M. kansasii, M. gordonae, and M. scrofulaceum) have substantial strain-to-strain variation in this region. These data suggest that each of the parasitic species has gone through a recent evolutionary bottleneck. Comparisons of tandem-repeat DNA from ancient and modern mycobacterial strains may allow this hypothesis to be tested directly.</p>  a0306-9877