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Ancient origins determine global biogeography of hot and cold desert cyanobacteria.

Bahl J, Lau MC, Smith GJ, Vijaykrishna D, Cary SC, Lacap DC, Lee CK, Papke RT, Warren-Rhodes KA, Wong FK, McKay CP, Pointing SB - Nat Commun (2011)

Bottom Line: Multilocus phylogenetic associations were dependent on contemporary climate with no evidence for distance-related patterns.These results indicate that global distribution of desert cyanobacteria has not resulted from widespread contemporary dispersal but is an ancient evolutionary legacy.This highlights the importance of considering temporal scales in microbial biogeography.

View Article: PubMed Central - PubMed

Affiliation: Duke-NUS Graduate Medical School, Singapore 169857.

ABSTRACT
Factors governing large-scale spatio-temporal distribution of microorganisms remain unresolved, yet are pivotal to understanding ecosystem value and function. Molecular genetic analyses have focused on the influence of niche and neutral processes in determining spatial patterns without considering the temporal scale. Here, we use temporal phylogenetic analysis calibrated using microfossil data for a globally sampled desert cyanobacterium, Chroococcidiopsis, to investigate spatio-temporal patterns in microbial biogeography and evolution. Multilocus phylogenetic associations were dependent on contemporary climate with no evidence for distance-related patterns. Massively parallel pyrosequencing of environmental samples confirmed that Chroococcidiopsis variants were specific to either hot or cold deserts. Temporally scaled phylogenetic analyses showed no evidence of recent inter-regional gene flow, indicating populations have not shared common ancestry since before the formation of modern continents. These results indicate that global distribution of desert cyanobacteria has not resulted from widespread contemporary dispersal but is an ancient evolutionary legacy. This highlights the importance of considering temporal scales in microbial biogeography.

No MeSH data available.


Related in: MedlinePlus

Relationship between genetic divergence and geographic distance among Chroococcidiopsis variants.Genetic differentiation was not significantly related to geographic distance (a) on the global scale (N=19, n=171), or for each of the phylogenetically defined clusters (b) cold (N=8, n=28), (c) hot 1 (N=6, n=15) or (d) hot 2 (N=5, n=10); where N denotes number of samples and n the resultant number of pairwise comparisons. The best-fit linear regression function, the coefficient of determination (R-square) and significance (p) of Mantel test are displayed for individual regression plots. A significance level (alpha) of 0.05 was applied.
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f4: Relationship between genetic divergence and geographic distance among Chroococcidiopsis variants.Genetic differentiation was not significantly related to geographic distance (a) on the global scale (N=19, n=171), or for each of the phylogenetically defined clusters (b) cold (N=8, n=28), (c) hot 1 (N=6, n=15) or (d) hot 2 (N=5, n=10); where N denotes number of samples and n the resultant number of pairwise comparisons. The best-fit linear regression function, the coefficient of determination (R-square) and significance (p) of Mantel test are displayed for individual regression plots. A significance level (alpha) of 0.05 was applied.

Mentions: Effects of climatic and substrate variables were evaluated by analysis of molecular variance (AMOVA, incorporating F Statistic) and phylogenetic test (P-test), whereas the effects of distance-related variables were assessed using the Mantel Statistic. Contemporary climate classification based on long-term mean annual temperature and precipitation data was significant in differentiating hot and cold clades (AMOVA, FCT=0.29147, P<0.00001). The phylogenetically informed delineation into 'hot' and 'cold' groupings provided the most parsimonious explanation (P-test, P<0.001) for the observed tree topology. On a global scale, genetic differentiation was not related to geographic distance (Mantel, R2=0.0055, P=0.169; Fig. 4a) or altitude (Mantel, R2=0.0011, P=0.601) for the homogenous substrate either within or between these major clades. We further tested the genetic and geographic distance relationship of the phylogenetically identified cold, hot 1 and hot 2 clades by the same method. On this more refined genetic scale, we were also unable to infer a correlation between genetic divergence and geographic distance (Fig. 4b–d). Analysis of relatively close desert locations showed a lack of relatedness between variants from the hot Death Valley desert versus the cold Utah Desert in North America (AMOVA, FST=0.84053, P=0.00586), the warm Turpan Depression versus the cold Tibetan tundra in China (AMOVA, FST=0.74756, P=0.00391), and the warm Atacama Desert versus the cold high altitude Bolivian Desert in South America (AMOVA, FST=0.93831, P<0.00001), whereas Antarctic variants were most closely affiliated with Arctic variants (FST=0.35368, P=0.18359).


Ancient origins determine global biogeography of hot and cold desert cyanobacteria.

Bahl J, Lau MC, Smith GJ, Vijaykrishna D, Cary SC, Lacap DC, Lee CK, Papke RT, Warren-Rhodes KA, Wong FK, McKay CP, Pointing SB - Nat Commun (2011)

Relationship between genetic divergence and geographic distance among Chroococcidiopsis variants.Genetic differentiation was not significantly related to geographic distance (a) on the global scale (N=19, n=171), or for each of the phylogenetically defined clusters (b) cold (N=8, n=28), (c) hot 1 (N=6, n=15) or (d) hot 2 (N=5, n=10); where N denotes number of samples and n the resultant number of pairwise comparisons. The best-fit linear regression function, the coefficient of determination (R-square) and significance (p) of Mantel test are displayed for individual regression plots. A significance level (alpha) of 0.05 was applied.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3105302&req=5

f4: Relationship between genetic divergence and geographic distance among Chroococcidiopsis variants.Genetic differentiation was not significantly related to geographic distance (a) on the global scale (N=19, n=171), or for each of the phylogenetically defined clusters (b) cold (N=8, n=28), (c) hot 1 (N=6, n=15) or (d) hot 2 (N=5, n=10); where N denotes number of samples and n the resultant number of pairwise comparisons. The best-fit linear regression function, the coefficient of determination (R-square) and significance (p) of Mantel test are displayed for individual regression plots. A significance level (alpha) of 0.05 was applied.
Mentions: Effects of climatic and substrate variables were evaluated by analysis of molecular variance (AMOVA, incorporating F Statistic) and phylogenetic test (P-test), whereas the effects of distance-related variables were assessed using the Mantel Statistic. Contemporary climate classification based on long-term mean annual temperature and precipitation data was significant in differentiating hot and cold clades (AMOVA, FCT=0.29147, P<0.00001). The phylogenetically informed delineation into 'hot' and 'cold' groupings provided the most parsimonious explanation (P-test, P<0.001) for the observed tree topology. On a global scale, genetic differentiation was not related to geographic distance (Mantel, R2=0.0055, P=0.169; Fig. 4a) or altitude (Mantel, R2=0.0011, P=0.601) for the homogenous substrate either within or between these major clades. We further tested the genetic and geographic distance relationship of the phylogenetically identified cold, hot 1 and hot 2 clades by the same method. On this more refined genetic scale, we were also unable to infer a correlation between genetic divergence and geographic distance (Fig. 4b–d). Analysis of relatively close desert locations showed a lack of relatedness between variants from the hot Death Valley desert versus the cold Utah Desert in North America (AMOVA, FST=0.84053, P=0.00586), the warm Turpan Depression versus the cold Tibetan tundra in China (AMOVA, FST=0.74756, P=0.00391), and the warm Atacama Desert versus the cold high altitude Bolivian Desert in South America (AMOVA, FST=0.93831, P<0.00001), whereas Antarctic variants were most closely affiliated with Arctic variants (FST=0.35368, P=0.18359).

Bottom Line: Multilocus phylogenetic associations were dependent on contemporary climate with no evidence for distance-related patterns.These results indicate that global distribution of desert cyanobacteria has not resulted from widespread contemporary dispersal but is an ancient evolutionary legacy.This highlights the importance of considering temporal scales in microbial biogeography.

View Article: PubMed Central - PubMed

Affiliation: Duke-NUS Graduate Medical School, Singapore 169857.

ABSTRACT
Factors governing large-scale spatio-temporal distribution of microorganisms remain unresolved, yet are pivotal to understanding ecosystem value and function. Molecular genetic analyses have focused on the influence of niche and neutral processes in determining spatial patterns without considering the temporal scale. Here, we use temporal phylogenetic analysis calibrated using microfossil data for a globally sampled desert cyanobacterium, Chroococcidiopsis, to investigate spatio-temporal patterns in microbial biogeography and evolution. Multilocus phylogenetic associations were dependent on contemporary climate with no evidence for distance-related patterns. Massively parallel pyrosequencing of environmental samples confirmed that Chroococcidiopsis variants were specific to either hot or cold deserts. Temporally scaled phylogenetic analyses showed no evidence of recent inter-regional gene flow, indicating populations have not shared common ancestry since before the formation of modern continents. These results indicate that global distribution of desert cyanobacteria has not resulted from widespread contemporary dispersal but is an ancient evolutionary legacy. This highlights the importance of considering temporal scales in microbial biogeography.

No MeSH data available.


Related in: MedlinePlus