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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

Idealized phylogenies of hypothetical scenarios for global distribution of desert cyanobacteria.Scenario a, assumes ubiquitous distribution resulting in mixed geographic regions and mixed environments within a phylogeny. Here, root divergence is a relatively recent event. Scenario b, assumes allopatric speciation resulting in distinct geographic regions and mixed environments within a phylogeny (that is, N America and Asia are monophyletic groups). Here, root divergence times correspond with formation of continents. Scenario c, assumes environmental selection corresponding to global climatic change, resulting in a phylogeny with mixed geographic regions and distinct environments. Here, the root divergence times are significantly older than known ages of formation of continents. Asterisks indicate monophyletic groups. Brown boxes and blue boxes indicate hot and cold desert locations, respectively.
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f2: Idealized phylogenies of hypothetical scenarios for global distribution of desert cyanobacteria.Scenario a, assumes ubiquitous distribution resulting in mixed geographic regions and mixed environments within a phylogeny. Here, root divergence is a relatively recent event. Scenario b, assumes allopatric speciation resulting in distinct geographic regions and mixed environments within a phylogeny (that is, N America and Asia are monophyletic groups). Here, root divergence times correspond with formation of continents. Scenario c, assumes environmental selection corresponding to global climatic change, resulting in a phylogeny with mixed geographic regions and distinct environments. Here, the root divergence times are significantly older than known ages of formation of continents. Asterisks indicate monophyletic groups. Brown boxes and blue boxes indicate hot and cold desert locations, respectively.

Mentions: This globally derived data set allowed for the testing of specific ecological and evolutionary scenarios (Fig. 2). If microbial dispersal were ubiquitous without environmental selection, random patterns of distribution would emerge (Fig. 2a). These deserts would effectively present a single-microbial habitat and biogeographic province3. Alternatively, if geographic isolation, rather than environmental selection, were the main driver of diversity then location-specific lineages would arise in different provinces regardless of microhabitat (Fig. 2b). For example, hot and cold deserts in the North America would share common ancestry. Finally, in a scenario in which environmental selection drives diversification lineages consisting of bacteria from cold and hot habitats would be observed (Fig. 2c). For example, the cyanobacteria from hot desert in Death Valley would share ancestry with hot deserts from other continents rather than with cyanobacteria from cold desert in Utah.


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)

Idealized phylogenies of hypothetical scenarios for global distribution of desert cyanobacteria.Scenario a, assumes ubiquitous distribution resulting in mixed geographic regions and mixed environments within a phylogeny. Here, root divergence is a relatively recent event. Scenario b, assumes allopatric speciation resulting in distinct geographic regions and mixed environments within a phylogeny (that is, N America and Asia are monophyletic groups). Here, root divergence times correspond with formation of continents. Scenario c, assumes environmental selection corresponding to global climatic change, resulting in a phylogeny with mixed geographic regions and distinct environments. Here, the root divergence times are significantly older than known ages of formation of continents. Asterisks indicate monophyletic groups. Brown boxes and blue boxes indicate hot and cold desert locations, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Idealized phylogenies of hypothetical scenarios for global distribution of desert cyanobacteria.Scenario a, assumes ubiquitous distribution resulting in mixed geographic regions and mixed environments within a phylogeny. Here, root divergence is a relatively recent event. Scenario b, assumes allopatric speciation resulting in distinct geographic regions and mixed environments within a phylogeny (that is, N America and Asia are monophyletic groups). Here, root divergence times correspond with formation of continents. Scenario c, assumes environmental selection corresponding to global climatic change, resulting in a phylogeny with mixed geographic regions and distinct environments. Here, the root divergence times are significantly older than known ages of formation of continents. Asterisks indicate monophyletic groups. Brown boxes and blue boxes indicate hot and cold desert locations, respectively.
Mentions: This globally derived data set allowed for the testing of specific ecological and evolutionary scenarios (Fig. 2). If microbial dispersal were ubiquitous without environmental selection, random patterns of distribution would emerge (Fig. 2a). These deserts would effectively present a single-microbial habitat and biogeographic province3. Alternatively, if geographic isolation, rather than environmental selection, were the main driver of diversity then location-specific lineages would arise in different provinces regardless of microhabitat (Fig. 2b). For example, hot and cold deserts in the North America would share common ancestry. Finally, in a scenario in which environmental selection drives diversification lineages consisting of bacteria from cold and hot habitats would be observed (Fig. 2c). For example, the cyanobacteria from hot desert in Death Valley would share ancestry with hot deserts from other continents rather than with cyanobacteria from cold desert in Utah.

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