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Bacterial genetic signatures of human social phenomena among M. tuberculosis from an Aboriginal Canadian population.

ABSTRACT: Despite a widespread global distribution and highly variable disease phenotype, there is little DNA sequence diversity among isolates of Mycobacterium tuberculosis. In addition, many regional population genetic surveys have revealed a stereotypical structure in which a single clone, lineage, or clade makes up the majority of the population. It is often assumed that dominant clones are highly adapted, that is, the overall structure of M. tuberculosis populations is the result of positive selection. In order to test this assumption, we analyzed genetic data from extant populations of bacteria circulating in Aboriginal communities in Saskatchewan, Canada. Demographic parameters of the bacterial population were estimated from archival epidemiological data collected over approximately 130 years since the onset of epidemic tuberculosis in the host communities. Bacterial genetic data were tested against neutral theory expectations and the local evolutionary history of M. tuberculosis investigated by phylogenetic analysis. Our findings are not consistent with positive selection on the bacterial population. Instead, we uncovered founder effects persisting over decades and barriers to gene flow within the bacterial population. Simulation experiments suggested that a combination of these neutral influences could result in the stereotypical structure of M. tuberculosis populations. Some aspects of population structure were suggestive of background selection, and data were on the whole consistent with combined effects of population bottlenecks, subdivision, and background selection. Neutral phenomena, namely, bottlenecks and partitions within populations, are prominent influences on the evolution of M. tuberculosis and likely contribute to restricted genetic diversity observed within this species. Given these influences, a complex evolutionary model will be required to define the relative fitness of different M. tuberculosis lineages and, ultimately, to uncover the genetic basis for its success as a pathogen.

SUBMITTER: Pepperell C

PROVIDER: S-EPMC2877553 | biostudies-other | 2010 Feb

REPOSITORIES: biostudies-other

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Bacterial genetic signatures of human social phenomena among M. tuberculosis from an Aboriginal Canadian population.

Pepperell Caitlin C Hoeppner Vernon H VH Lipatov Mikhail M Wobeser Wendy W Schoolnik Gary K GK Feldman Marcus W MW

Molecular biology and evolution 20091027 2

Despite a widespread global distribution and highly variable disease phenotype, there is little DNA sequence diversity among isolates of Mycobacterium tuberculosis. In addition, many regional population genetic surveys have revealed a stereotypical structure in which a single clone, lineage, or clade makes up the majority of the population. It is often assumed that dominant clones are highly adapted, that is, the overall structure of M. tuberculosis populations is the result of positive selectio ...[more]

PMID: 19861642

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Project description:BackgroundEarly childhood social and emotional development underpins later social, emotional, academic and other outcomes. The first aim of this study was to explore the association between child, family and area-level characteristics associated with developmental vulnerability, amongst Aboriginal and non-Aboriginal children in their first year of school. The second aim was to quantify the magnitude of the social and emotional developmental inequalities between Aboriginal and non-Aboriginal children and the extent to which differences in socioeconomic disadvantage and perinatal characteristics explained this inequality.MethodsThis retrospective cohort study used cross-sectoral data linkage to identify and follow participants from birth to school age. In this way, social and emotional development was examined in 7,384 Aboriginal and 95,104 non-Aboriginal children who were included in the Australian Early Development Census in their first year of full-time school in New South Wales (NSW) in 2009 or 2012 and had a birth registration and/or perinatal record in NSW. The primary outcome measures were teacher-reported social competence and emotional maturity as measured using the Australian version of the Early Development Instrument.ResultsThe mean age at the start of the school year for children in the study sample was 5.2 years (SD = 0.36 years). While 84% of Aboriginal children scored favourably - above the vulnerability threshold - for social competence and 88% for emotional maturity, Aboriginal children were twice as likely as non-Aboriginal children to be vulnerable on measures of social development (RR = 2.00; 95%CI, 1.89-2.12) and had 89% more risk of emotional vulnerability (RR = 1.89; 95%CI, 1.77-2.02). The inequality between Aboriginal and non-Aboriginal children was largely explained by differences in the socioeconomic and perinatal health characteristics of children and families. Thus, after adjusting for differences in measures of socioeconomic advantage and disadvantage (Model 2), the relative risk was attenuated to 1.31 (95% CI: 1.23-1.40) on the social competence domain and 1.24 (95% CI, 1.15-1.33) on the emotional maturity domain. Child, family and area-level characteristics associated with vulnerability were identified.ConclusionsMost of the gap in early childhood social and emotional development between Aboriginal and non-Aboriginal children can be attributed to socioeconomic and early life health disadvantage. Culturally safe health and social policies addressing the socioeconomic and health inequalities experienced by Aboriginal children are urgently required.

Dataset Information

Bacterial genetic signatures of human social phenomena among M. tuberculosis from an Aboriginal Canadian population.

Publications

Bacterial genetic signatures of human social phenomena among M. tuberculosis from an Aboriginal Canadian population.

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