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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

Temporal phylogeny for Chroococcidiopsis variants.Variants were recovered from hot and cold deserts worldwide as shown in Supplementary Table S1. The tree was generated using a Bayesian relaxed-clock phylogenetic approach16 of the 16S-ITS-23S rDNA regions to estimate divergence dates. The age of the common ancestor for Chroococcidiopsis was estimated with a 95% Bayesian confidence interval, using fossil ancestors for calibration1314. Blue bars at nodes indicate 95% credible intervals for divergence events. Temporal scale is shown in millions of years.
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f3: Temporal phylogeny for Chroococcidiopsis variants.Variants were recovered from hot and cold deserts worldwide as shown in Supplementary Table S1. The tree was generated using a Bayesian relaxed-clock phylogenetic approach16 of the 16S-ITS-23S rDNA regions to estimate divergence dates. The age of the common ancestor for Chroococcidiopsis was estimated with a 95% Bayesian confidence interval, using fossil ancestors for calibration1314. Blue bars at nodes indicate 95% credible intervals for divergence events. Temporal scale is shown in millions of years.

Mentions: A temporal phylogeny calibrated using fossil records1314 that have been shown as robust calibration points for cyanobacterial phylogenies15, was constructed using a Bayesian relaxed-clock analysis of the complete, unambiguously aligned, 16S-ITS-23S rRNA gene regions to estimate the divergence times of the globally distributed Chroococcidiopsis variants (Fig. 3, Supplementary Figs S1–S5 show all individual and combined gene trees). We used a relaxed phylogenetic approach16 to estimate phylogeny and divergence times while taking into account uncertainties in evolutionary rates and calibration times17. Briefly, a 16S rRNA gene cyanobacterial phylogeny was constructed using the age of two fossilized ancestors as calibration points for estimation of evolutionary rates and timing of divergence events (Supplementary Fig. S1). The estimated age of the common ancestor for Chroococcidiopsis was then incorporated as a previous constraint on subsequent Bayesian relaxed-clock analysis of the complete, unambiguously aligned, 16S-ITS-23S rRNA gene regions to estimate the divergence times of the globally distributed Chroococcidiopsis variants (Supplementary Figs S2–S5).


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)

Temporal phylogeny for Chroococcidiopsis variants.Variants were recovered from hot and cold deserts worldwide as shown in Supplementary Table S1. The tree was generated using a Bayesian relaxed-clock phylogenetic approach16 of the 16S-ITS-23S rDNA regions to estimate divergence dates. The age of the common ancestor for Chroococcidiopsis was estimated with a 95% Bayesian confidence interval, using fossil ancestors for calibration1314. Blue bars at nodes indicate 95% credible intervals for divergence events. Temporal scale is shown in millions of years.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f3: Temporal phylogeny for Chroococcidiopsis variants.Variants were recovered from hot and cold deserts worldwide as shown in Supplementary Table S1. The tree was generated using a Bayesian relaxed-clock phylogenetic approach16 of the 16S-ITS-23S rDNA regions to estimate divergence dates. The age of the common ancestor for Chroococcidiopsis was estimated with a 95% Bayesian confidence interval, using fossil ancestors for calibration1314. Blue bars at nodes indicate 95% credible intervals for divergence events. Temporal scale is shown in millions of years.
Mentions: A temporal phylogeny calibrated using fossil records1314 that have been shown as robust calibration points for cyanobacterial phylogenies15, was constructed using a Bayesian relaxed-clock analysis of the complete, unambiguously aligned, 16S-ITS-23S rRNA gene regions to estimate the divergence times of the globally distributed Chroococcidiopsis variants (Fig. 3, Supplementary Figs S1–S5 show all individual and combined gene trees). We used a relaxed phylogenetic approach16 to estimate phylogeny and divergence times while taking into account uncertainties in evolutionary rates and calibration times17. Briefly, a 16S rRNA gene cyanobacterial phylogeny was constructed using the age of two fossilized ancestors as calibration points for estimation of evolutionary rates and timing of divergence events (Supplementary Fig. S1). The estimated age of the common ancestor for Chroococcidiopsis was then incorporated as a previous constraint on subsequent Bayesian relaxed-clock analysis of the complete, unambiguously aligned, 16S-ITS-23S rRNA gene regions to estimate the divergence times of the globally distributed Chroococcidiopsis variants (Supplementary Figs S2–S5).

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