| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Centre for Molecular Microbiology and Infectious Diseases, Imperial College of Science, Technology and Medicine, London SW7 2AZ, UK
2 School of Geography, Archaeology and Palaeoecology, Queen's University Belfast, Belfast BT7 1NN, UK
3 Department of Genetics, Institute of Child Health, University College London, London WC1N 1EH, UK
4 Peter the Great Museum of Anthropology and Ethnography (Kunstkamera), 3 University Embankment, St Petersburg 199034, Russia
Correspondence
G. Michael Taylor
gm.taylor{at}ucl.ac.uk
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
Present address: Centre for Infectious Diseases and International Health, Windeyer Institute, University College London, 46 Cleveland Street, London W1T 4JF, UK.
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
). The human-to-human transmission of tuberculosis is reliant on the existence of groups of individuals living in close proximity to one another.
The bovine form of tuberculosis is transmitted from animals (such as cattle) to humans through infected milk or meat and is consequently primarily a disease of the stomach and intestinal tract, although it can cause respiratory disease (Cotter et al., 1996; LoBue et al., 2004; Thompson et al., 1993). In developed countries such as the UK, where control measures and herd testing have been in place since the 1930s, bovine tuberculosis accounts for <1 % of human tuberculosis cases and tends to be a disease associated with those in close proximity to livestock, such as farmers, veterinary surgeons and abattoir workers (Gutierrez et al., 1997; Robinson et al., 1988; Smith et al., 2004). As such, it is considered to be a spillover infection in humans and is seldom self-maintaining (O'Reilly & Daborn, 1995).
In a small percentage of cases, tuberculosis may affect the skeleton, giving rise to characteristic lytic lesions with minimal new bone formation (Ortner & Putschar, 1985). Many such cases have been identified in the archaeological record. However, based on morphological examination of osteological lesions, palaeopathologists cannot distinguish between infection due to M. tuberculosis or M. bovis (Roberts & Buikstra, 2003; Ortner, 1999). Dependent upon DNA survival, polymorphic loci in the genomes of these two organisms permit this distinction to be made, even in ancient cases (Taylor et al., 1999). Whilst a number of groups have now successfully amplified fragmented mycobacterial DNA from archaeological human remains, relatively few have applied genetic typing methods. A recent review of the tuberculosis ancient DNA (aDNA) literature identified the potential for such analyses to contribute to the debate on the evolution of the M. tuberculosis (MTB) complex and to the nature of the host–pathogen interaction (Donoghue et al., 2004).
In the present study we examined osteological samples obtained from five individuals with skeletal evidence of tuberculosis retrieved from the cemetery of Aymyrlyg in the Ulug-Khemski region of Tuva, South Siberia. South Siberia is one of the areas of the world with the oldest traditions of pastoralism and it was recognized that there was the potential to identify biomolecular evidence for the bovine form of the disease, which has previously eluded identification (Donoghue et al., 2004). As such, the objectives of the aDNA analysis were to confirm that the lesions were due to tuberculosis and to determine whether the individuals had been infected with either M. bovis or M. tuberculosis.
|
METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
) yielded dates ranging from approximately 1761 to 2199 years BP, placing the remains within the Iron Age period of South Siberia. This dates burials XXXI.34 and XXXI.77 to the transition period between the Uyuk (7th–3rd centuries BC) and Shurmak (2nd century BC–5th century AD) Cultures and the other three burials within the later Shurmak or Synnchyurek Culture.
|
).
PCR.
Hot-staRT-PCR was performed in a final volume of 25 µl using the Excite Core kit from BioGene with minor modification to the manufacturer's instructions. Additional Taq polymerase (0.4 µl, 2 U) was added to the master mix to allow for PCR inhibitors in bone extracts. After an initial denaturation step (8 min at 95 °C), 45 cycles of amplification were performed as follows: denaturation at 95 °C for 10 s, annealing at 58 to 62 °C for 30 s, extension at 72 °C for 20 s. SYBR Green was included in the PCR master mixes at a final dilution of 1/55 000, and reactions were performed and monitored with a Corbett RotorGene 3000 real-time PCR platform. Melting analysis was performed with the RotorGene software and all products were also run on 3 % agarose checker gels. Cycle sequencing of PCR products was performed as previously reported (Taylor et al., 2003).
Extracts from the Aymyrlyg burials were screened using two methods which amplify repetitive elements specific to the MTB complex, IS6110 and IS1081 (Dziadek et al., 2001). Multi-copy genes and repetitive elements such as these make good targets when attempting to demonstrate the presence of pathogen DNA in the archaeological record (Cano, 1996). IS6110 is multi-copy in the majority of extant strains of M. tuberculosis (Plikaytis et al., 1993). Most isolates of the MTB complex contain six copies of the insertion sequence IS1081 (Collins & Stephens, 1991), so this element is therefore theoretically a better target when testing for M. tuberculosis isolates, which have few copies or even lack IS6110 (Yuen et al., 1993), and M. bovis, which usually contains a single IS6110 copy in the direct repeat (DR) region of the genome (Hermans et al., 1991). However, variation in IS6110 copy number has been associated with M. bovis isolates of different geographical origin (Liebana et al., 1997).
Polymorphic loci and regions of difference.
The extracts were also tested using a series of genotyping PCRs to place any positive cases within the evolutionary scenario for the MTB complex (Brosch et al., 2002). This scheme has been compiled using comparative genomics of extant strains of members of the MTB complex (Mycobacterium canetti, M. tuberculosis, M. africanum, M. microti, M. bovis and M. bovis BCG). The assays included analysis of polymorphic loci within the oxyR pseudogene (oxyR285) and the pyrazinamidase gene (pncA159), which can be used to distinguish between M. tuberculosis and M. bovis (Scorpio et al., 1997; Sreevatsan et al., 1996). PCR primers flanking deletions within the MTB complex were also used to assess the status of key regions of difference (RD). The deletions tested for were RD12, RD13, RD4 and RD17 and TbD1. This last deletion has been used to distinguish ‘ancestral’ from ‘modern’ isolates of TB, as the region is retained only in M. bovis and in a subgroup of the ancestral group 1 isolates of M. tuberculosis (Brosch et al., 2002; Sreevatsan et al., 1997). However, it may be more appropriate to associate the presence or absence of the TbD1 locus with geographical areas or distinct lineages, as the population genetics of M. tuberculosis is now seen as being geographically related (Gagneux et al., 2006). Primer sequences for novel RD methods are shown in Table 2. Details of the TbD1, the oxyR285 and the pncA169 methods have been previously reported (Taylor et al., 2005).
|
; Taylor et al., 2006). The focus was on physical barriers with separate areas for extraction, PCR set-up and analysis. Surfaces and equipment (centrifuges, rotors, pipettes, etc.) were cleaned before each experiment. Filter tips were used routinely. Control extractions were used to monitor the efficacy of these procedures. Template (water) blanks were alternated with samples in the PCR machines to screen for contamination. Positive controls were either excluded from amplifications or were run in separate laboratories to minimize the opportunities for contaminating aDNA extracts.
Reproducibility
Imperial College, London.
Experiments were undertaken by two of us (R. H. and G. M. T.) separated by a period of 3 months to assess the reproducibility of any positive findings. R. H. assayed extracts with IS6110, IS1081 and oxyR285 methods, G. M. T. with these loci plus pncA169, all RD PCRs and TbD1 primers. Separate bone extracts were used for these two series of experiments.
Second-centre confirmation.
Author P. R. analysed fresh extracts at a second laboratory, in this case the Department of Genetics at the Institute of Child Health, University College London. No research on tuberculosis had previously been conducted within this department. The experiments were limited to confirmation of the MTB complex by IS1081 PCR and oxyR285 genotyping to determine species. All primers and PCR reagents for this phase of the study were newly synthesized or purchased separately.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
). Three of the skeletons displayed infective lesions that are considered to be indicative of tuberculosis. In addition, two individuals displayed new bone formation on the anterior surfaces of one or more of their vertebrae. It was considered possible that these lesions were due to some form of gastrointestinal infection, which could have been tuberculosis (Table 1). All of the skeletons were Iron Age in date (Table 1) and came from a society that is believed to have practised a semi-nomadic pastoralist form of economy. This would have taken the form of a pattern of repeated seasonal migrations or ‘shifts' with herd animals within a well-defined territory. The chief herding animals of peoples from this culture were sheep, goats and cattle. Horses were also kept and would have been used for transport, as would cattle and yaks (Vainshtein, 1980).
Mycobacterial DNA was successfully amplified and genotyped from four of the five individuals with skeletal lesions. The PCR results for the screening and genotyping PCRs are summarized in Table 3. Extracts (n=8) prepared from four of the burials were found to be IS1081 positive, a sensitive marker for the MTB complex. Genotyping PCRs were applied to the more strongly positive extracts from each of the four positive cases. Amplification and sequencing of oxyR285 from all four cases showed an adenine (A) base at this locus, indicative of an M. bovis isolate (cf. G in M. tuberculosis). These findings were replicated independently by both workers at Imperial College and by author P. R. at the second centre in University College London.
|
). Extraction and template blanks were consistently negative, showing that measures to avoid contamination were effective. Skeleton XXXI.101, a 7.5–8.5-year-old child, was always negative for IS1081 and IS6110 and so other less sensitive PCRs were not applied to this case. However, this individual displayed Pott's disease of the spine and other characteristic lesions of tuberculosis, and it is considered likely that the negative result may have been due to the poorer preservation of the immature bone relative to the adult remains.
PCR performed with primers flanking the RD12, RD13 and RD4 deletions yielded products of the expected size, showing that these deletion events had occurred in the strains recovered from the Aymyrlyg burials. The status of the RD17 deletion was studied in two cases, burials XXX1.77 and XXX1.85. Use of flanking primers for RD17 failed to produce a specific amplicon but internal primers generated products of the expected size (96 bp), in both cases. The identity of the PCR product was confirmed in burial XXX1.77 by sequencing.
Extracts prepared from burials XXX1.63 and XXX1.77 were generally more robust in terms of PCR products obtained using the RD single-copy PCR methods, suggesting that template integrity was better in these cases. All the positive tests indicated that four out of five of the Siberian individuals were infected with bovine tuberculosis. The fact that M. bovis was the species involved may explain the relatively poor IS6110 data, as this marker is single copy in the majority of extant M. bovis strains, and this may also be the case in these older isolates.
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
). In contrast, limited synonymous nucleotide diversity in present-day MTB complex mycobacteria suggests that this detachment from the progenitor group and subsequent clonal expansion has taken place within a narrower time-frame, estimated at up to 35 000 years BP (Gutierrez et al., 2005; Sreevatsan et al., 1997).
In recent years, bioarchaeological studies have begun to examine cases of tuberculosis from the archaeological record and to obtain genotyping data. Evidence for M. tuberculosis as the causative species has been obtained from mediaeval sites in Europe (Taylor et al., 1999; Mays et al., 2001; Fletcher et al., 2003), from Iron Age Britain (Taylor et al., 2005) and from Middle Kingdom Egypt (Zink et al., 2003). Limited evidence from spoligotyping of the Egyptian cases has shown an absence of spacers 33–36 in the DR region of the genome, suggesting strains belonging to phylogenetic group 2 in the Musser model of the MTB complex (Sreevatsan et al., 1997). Isolates of M. tuberculosis from this group have lost the TbD1 region, and this work indicates that this deletion may have occurred at least 2500 years BP. Loss of TbD1 is specific to M. tuberculosis strains and is a marker which has been used to distinguish ‘modern’ strains from those which are more closely related to the common ancestor of the complex and those from certain geographical origins (Brosch et al., 2002; Sun et al., 2004). Consistent with the antiquity of this event implied from the spoligotyping of Egyptian remains, we have recently reported that the TbD1 region had been deleted in a strain from an Iron Age burial with Pott's disease from Dorset, UK (Taylor et al., 2005). ‘Modern’ strains may be older than the term suggests. Zink et al. (2003) also observed spoligotype fingerprints consistent with M. africanum in older Egyptian burials but found no evidence for bovine tuberculosis.
The present study is believed to be the first to document bovine tuberculosis in human remains and shows that the RD status and polymorphisms in these Iron Age cases are in agreement with the evolutionary scheme proposed by Brosch et al. (2002). Tests for RDs 12, 13 and 4 showed that these loci had all been deleted from the Siberian cases whereas the TbD1 and RD17 regions were still present. These findings, together with characteristic nucleotide polymorphisms in pncA169 and oxyR285, are typical of classic M. bovis, so it is probable that these isolates were derived from strains which had originally adapted to cattle. Our findings indicate that the RD4 deletion associated with M. bovis had already been lost from the genome at least 2000 years BP. For the most part, little is known of the absolute chronology of the deletions in the bovine lineage, although loss of five regions occurring over a 50 year period of intensive passage in laboratories worldwide has been documented in BCG vaccine strains (Behr et al., 1999).
Based on deletion subset patterns in M. bovis isolates, there are three lineages (a–c) in which the RD17 region is present and one (d) in which it has been lost (Mostowy et al., 2005). The majority of UK bovine spoligotypes, including the sequenced strain AF 2122/97, fall into this latter group, having lost RD17. The region is retained in two spoligotypes, GB35 and GB54, both relatively rare causes of bovine tuberculosis in the UK but more frequently reported in France (Haddad et al., 2001). The observation that the strain of M. bovis infecting burials XXX1.77 and XXX1.85 retained RD17 therefore distinguishes them from strains commonly isolated in the UK. Further sampling would be necessary to identify from which of the three lineages with RD17 this strain was derived.
As bovine tuberculosis is not considered to be self-maintaining in man (O'Reilly & Daborn, 1995) we infer that disease in these human remains, spanning several centuries, reflects continued exposure of the population to an infected animal reservoir host or hosts. During the Bronze Age, the mountain-steppe tribes of Tuva probably kept more cattle than sheep or goats (Gryaznov, 1969). By the Iron Age, sheep and goats almost certainly accounted for more than half of all livestock (Vainshtein, 1980). Therefore, it is interesting to note that the disease was not caused by the caprine-adapted variant of M. bovis (‘M. caprae’) first identified in Spanish goats. This is characterized by retention of the RD4 region and the pncA169C mutation usually associated with M. tuberculosis. Although first isolated from goats, this member of the M. bovis lineage can also cause disease in cattle (Aranaz et al., 2003). Next in frequency after sheep and goats would have come horses and cattle. Cattle husbandry continued as an important part of the economy for milk, meat and traction. During harsh winters, cows' milk would have been fed to young lambs and kids when grazing was difficult (Vainshtein, 1980), so these animals, as well as cattle, may have acted as reservoirs of disease. It is recognized that classic M. bovis has a wide host range and can cause disease in sheep and goats, although in some countries, such as Britain, this is a relatively rare event (Malone et al., 2003). It would therefore be interesting to study the faunal remains from Amyrylyg for M. bovis aDNA, but this poses a number of problems due to the disarticulated, fragmentary and often scavenged nature of faunal remains at archaeological sites. This is compounded by the degree to which the skeleton may be affected in different species, the age at slaughter and the lack of diagnostic criteria for skeletal evidence of tuberculosis in animals (Mays, 2005).
DNA from archaeological contexts is invariably degraded, and sampling is destructive and usually regulated; hence the biomolecular evidence which can be recovered from human remains is very limited. However, several lines of evidence have shown M. bovis DNA in skeletal remains from these semi-nomadic Iron Age pastoralists. We speculate that this resulted from their continued close proximity to infected cattle or to another species which acted as either a spillover or reservoir host of the disease. Consumption of raw milk and poorly cooked meat are the most probable routes of infection. This was certainly the situation for developed Western countries in the era before various control measures, such as herd testing and pasteurization of milk, were introduced (O'Reilly & Daborn, 1995).
|
ACKNOWLEDGEMENTS |
|---|
Edited by: F. A. Rainey
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONREFERENCES |
|---|
to species rank as Mycobacterium caprae comb. nov., sp. nov. Int J Syst Evol Microbiol 53, 1785–1789.Behr, M. A., Wilson, M. A., Gill, W. P., Salamon, H., Schoolnik, G. K., Rane, S. & Small, P. (1999). Comparative genomics of BCG vaccines by whole-genome DNA microarray. Science 284, 1520–1523.
Bronk-Ramsey, C. (2000). OxCal v3.5 program. Available at http://c14.arch.ox.ac.uk/oxcal/OxCalPlot.html
Brosch, R., Gordon, S. V., Marmiesse, M., Brodin, P., Buchrieser, C., Eiglmeier, K., Garnier, T., Gutierrez, C., Hewinson, G. & other authors (2002). A new evolutionary scenario for the Mycobacterium tuberculosis complex. Proc Natl Acad Sci U S A 99, 3684–3689.
Buikstra, J. E. & Ubelaker, D. H. (1994). Standards for Data Collection from Human Skeletal Remains. Research Series no. 44. Fayetteville: Arkansas Archaeological Survey Press.
Cano, R. J. (1996). Analysing ancient DNA. Endeavour 20, 162–167.[CrossRef]
Collins, D. M. & Stephens, D. M. (1991). Identification of an insertion sequence, IS1081, in Mycobacterium bovis. FEMS Microbiol Lett 67, 11–15.[Medline]
Cotter, T. P., O'Shaughnessy, E., Sheehan, S., Cryan, B. & Bredin, C. P. (1996). Human Mycobacterium bovis infection in the south-west of Ireland 1983–1992: a comparison with M. tuberculosis. Ir Med J 89, 62–63.[Medline]
Donoghue, H. D., Spigelman, M., Greenblatt, C. L., Lev-Maor, G., Bar-Gal, G. K., Matheson, C., Vernon, K., Nerlick, A. G. & Zink, A. R. (2004). Tuberculosis: from prehistory to Robert Koch, as revealed by ancient DNA. Lancet Infect Dis 4, 584–592.[CrossRef][Medline]
Dziadek, J., Sajduda, A. & Borun, T. M. (2001). Specificity of insertion sequence-based PCR assays for Mycobacterium tuberculosis complex. Int J Tuberc Lung Dis 5, 569–574.[Medline]
Ferembach, D., Schwidetzky, I. & Stloukal, M. (1980). Recommendations for age and sex diagnoses of skeletons. J Hum Evol 9, 517–549.
Fletcher, H. A., Donoghue, H. D., Taylor, G. M., van der Zanden, A. G. M. & Spigelman, M. (2003). Molecular analysis of Mycobacterium tuberculosis DNA from a family of 18th century Hungarians. Microbiology 149, 143–151.
Gagneux, S., DeReimer, K., Van, T., Kato-Maeda, M., de Jong, B. C., Narayanan, S., Nicol, M., Nieman, S., Kremer, K. & other authors (2006). Variable host–pathogen compatibility in Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 103, 2869–2873.
Gryaznov, M. (1969). The Ancient Civilization of South Siberia. London: Barrie & Rockliff: the Cresset Press.
Gutierrez, M., Samper, S., Jimenez, M. S., van Embden, J. D., Marin, J. F. & Martin, C. (1997). Identification by spoligotyping of a caprine genotype in Mycobacterium bovis strains causing human tuberculosis. J Clin Microbiol 35, 3328–3330.[Abstract]
Gutierrez, M. C., Brisse, S., Brosch, R., Fabre, M., Omais, B., Marmiesse, M., Supply, P. & Vincent, V. (2005). Ancient origin and gene mosaicism of the progenitor of Mycobacterium tuberculosis. PloS Pathogens 1, 1–7.
Haddad, N., Ostyn, A., Karoui, C., Masselot, M., Thorel, M. F., Hughes, S. L., Inwald, J., Hewinson, R. G. & Durand, B. (2001). Spoligotype diversity of Mycobacterium bovis strains isolated in France from 1979 to 2000. J Clin Microbiol 39, 3623–3632.
Hermans, P. W., van Soolingen, D., Bik, E. M., de Haas, P. E., Dale, J. W. & van Embden, J. D. (1991). Insertion element IS987 from Mycobacterium bovis BCG is located in a hot-spot integration region for insertion elements in Mycobacterium tuberculosis complex strains. Infect Immun 59, 2695–2705.
Liebana, E., Aranaz, A., Dominguez, L., Mateos, A., Gonzalez-Llamazares, O., Rodriguez-Ferri, E. F., Domingo, M., Vidal, D. & Cousins, D. (1997). The insertion element IS6110 is a useful tool for DNA fingerprinting of Mycobacterium bovis isolates from cattle and goats in Spain. Vet Microbiol 54, 223–233.[CrossRef][Medline]
LoBue, P. A., Betancourt, W., Cowan, L., Seli, L., Peter, C. & Moser, K. S. (2004). Identification of a familial cluster of pulmonary Mycobacterium bovis disease. Int J Tuberc Lung Dis 8, 1142–1146.[Medline]
Malone, F. E., Wilson, E. C., Pollock, J. M. & Skuce, R. A. (2003). Investigations into an outbreak of tuberculosis in a flock of sheep in contact with tuberculous cattle. J Vet Med B Infect Dis Vet Public Health 50, 500–504.[Medline]
Mays, S. (2005). Tuberculosis as a zoonotic disease in antiquity. In Diet and Health in Past Animal Populations: Current Research and Future Directions, pp. 125–134. Edited by J. Davies, M. Fabi
, I. Mainland, M. Richards & R. Thomas. Oxford: Oxbow.
Mays, S. A., Taylor, G. M., Legge, A. J., Young, D. B. & Turner-Walker, G. A. (2001). Palaeopathological and biomolecular study of tuberculosis in a medieval skeletal collection from England. Am J Phys Anthropol 114, 298–311.[CrossRef][Medline]
Mostowy, S., Inwald, J., Gordon, S., Martin, C., Warren, R., Kremer, K., Cousins, D. & Behr, M. A. (2005). Revisiting the evolution of Mycobacterium bovis. J Bacteriol 187, 6386–6395.
O'Reilly, L. M. & Daborn, C. J. (1995). The epidemiology of Mycobacterium bovis infections in animals and man: a review. Tuber Lung Dis 76 (suppl. 1), 1–46.[Medline]
Ortner, D. J. (1999). Palaeopathology: implications for the history and evolution of tuberculosis. In Tuberculosis Past and Present, pp. 255–261. Edited by G. Pálfi, O. Dutour, J. Deák & I. Hutás. Budapest: Golden Books/Tuberculosis Foundation.
Ortner, D. J. & Putschar, W. G. J. (1985). The Identification of Pathological Conditions in Human Skeletal Remains. Washington: Smithsonian Institution Press.
Plikaytis, B. B., Crawford, J. T., Woodley, C. L., Butler, W. R., Eisenach, K. D., Cave, M. D. & Shinnick, T. M. (1993). Rapid, amplification-based fingerprinting of Mycobacterium tuberculosis. J Gen Microbiol 139, 1537–1542.[Medline]
Roberts, C. A. & Buikstra, J. E. (2003). The Bioarchaeology of Tuberculosis: a Global View on a Re-emerging Disease. Tampa: University Press of Florida.
Robinson, P., Morris, D. & Antic, R. (1988). Mycobacterium bovis as an occupational hazard in abattoir workers. Aust N Z J Med 18, 701–703.[Medline]
Scorpio, A., Collins, D., Whipple, D., Cave, D., Bates, J. & Zhang, Y. (1997). Rapid differentiation of bovine and human tubercle bacilli based on a characteristic mutation in the bovine pyrazinamidase gene. J Clin Microbiol 35, 106–110.[Abstract]
Smith, R. M., Drobniewski, F., Gibson, A., Montague, J. D., Logan, M. N., Hunt, D., Hewinson, G., Salmon, M. R. & O'Neill, B. (2004). Mycobacterium bovis infection, United Kingdom. Emerg Infect Dis 10, 539–541.[Medline]
Sreevatsan, S., Escalante, P., Pan, X., Gillies, D. A., Siddiqui, S., Khalaf, C. N., Kreiswirth, B. N., Bifani, P. & Adams, L. G. (1996). Identification of a polymorphic nucleotide in oxyR specific for Mycobacterium bovis. J Clin Microbiol 34, 2007–2010.[Abstract]
Sreevatsan, S., Pan, X., Stockbauer, K. E., Connell, N. D., Kreiswirth, B. N., Whitman, S. & Musser, J. M. (1997). Restricted structural gene polymorphism in the Mycobacterium tuberculosis complex indicates evolutionarily recent global dissemination. Proc Natl Acad Sci U S A 94, 9869–9874.
Stuiver, M., Reimer, P. J., Bard, E., Beck, J. W., Burr, G. S., Hughen, K. A., Kromer, B., McCormac, G., van der Plicht, J. & Spurk, M. (1998). INTCAL98 radiocarbon age calibration, 24000-0 cal BP. Radiocarbon 40, 1041–1083.
Sun, Y. J., Lee, A. S., Ng, S. T., Ravindran, S., Kremer, K., Bellamy, R., Wong, S. Y., van Soolingen, D., Supply, P. & Paton, N. I. (2004). Characterization of ancestral Mycobacterium tuberculosis by multiple genetic markers and proposal of genotyping strategy. J Clin Microbiol 42, 5058–5064.
Taylor, G. M., Goyal, M., Legge, A. J., Shaw, R. J. & Young, D. (1999). Genotypic analysis of Mycobacterium tuberculosis from medieval human remains. Microbiology 145, 899–904.[Abstract]
Taylor, G. M., Stewart, G. R., Cooke, M., Chaplin, S., Ladva, S., Kirkup, J., Palmer, S. & Young, D. B. (2003). Koch's Bacillus – a look at the first isolate of Mycobacterium tuberculosis from a modern perspective. Microbiology 149, 3213–3220.
Taylor, G. M., Young, D. B. & Mays, S. A. (2005). Genotypic analysis of the earliest known prehistoric case of tuberculosis in Britain. J Clin Microbiol 43, 2236–2240.
Taylor, G. M., Watson, C. L., Bouwman, A. S., Lockwood, D. N. J. & Mays, S. A. (2006). Variable nucleotide tandem repeat (VNTR) typing of two palaeopathological cases of lepromatous leprosy from Mediaeval England. J Arch Sci 33, 1569–1579.
Thompson, P. J., Cousins, D. V., Gow, B. L., Collins, D. M., Williamson, B. H. & Dagnia, H. T. (1993). Seals, seal trainers, and mycobacterial infection. Am Rev Respir Dis 147, 164–167.[Medline]
Vainshtein, S. (1980). Nomads of South Siberia: the Pastoral Economies of Tuva. Cambridge: Cambridge University Press.
Yuen, L. K., Ross, B. C., Jackson, K. M. & Dwyer, B. (1993). Characterization of Mycobacterium tuberculosis strains from Vietnamese patients by Southern blot hybridization. J Clin Microbiol 31, 1615–1618.
Zink, A. R., Sola, C., Reischl, U., Grabner, W., Rastogi, N., Wolf, H. & Nerlich, A. G. (2003). Characterization of Mycobacterium tuberculosis complex DNAs from Egyptian mummies by spoligotyping. J Clin Microbiol 41, 359–367.
Received 4 September 2006;
revised 26 November 2006;
accepted 19 December 2006.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
