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Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum

BACKGROUND: Microorganisms are ubiquitous, yet we are only beginning to understand their diversity and population structure. Social amoebae (Dictyostelia) are a diverse group of unicellular eukaryotic microbes that display a unique social behaviour upon starvation in which cells congregate and then...

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Autores principales: Mehdiabadi, Natasha J, Kronforst, Marcus R, Queller, David C, Strassmann, Joan E
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2824659/
https://www.ncbi.nlm.nih.gov/pubmed/20089169
http://dx.doi.org/10.1186/1471-2148-10-17
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author Mehdiabadi, Natasha J
Kronforst, Marcus R
Queller, David C
Strassmann, Joan E
author_facet Mehdiabadi, Natasha J
Kronforst, Marcus R
Queller, David C
Strassmann, Joan E
author_sort Mehdiabadi, Natasha J
collection PubMed
description BACKGROUND: Microorganisms are ubiquitous, yet we are only beginning to understand their diversity and population structure. Social amoebae (Dictyostelia) are a diverse group of unicellular eukaryotic microbes that display a unique social behaviour upon starvation in which cells congregate and then some die to help others survive and disperse. The genetic relationships among co-occurring cells have a major influence on the evolution of social traits and recent population genetic analysis found extensive genetic variation and possible cryptic speciation in one dictyostelid species (Dictyostelium purpureum). To further characterize the interplay among genetic variation, species boundaries, social behaviour, and reproductive isolation in the Dictyostelia, we conducted phylogenetic analyses and mating experiments with the geographically widespread social amoeba Dictyostelium giganteum. RESULTS: We sequenced approximately 4,000 basepairs of the nuclear ribosomal DNA from 24 isolates collected from Texas, Michigan, Massachusetts, Virginia, and Wisconsin and identified 16 unique haplotypes. Analyses of the sequence data revealed very little genetic differentiation among isolates and no clear evidence of phylogenetic structure, although there was evidence for some genetic differentiation between the Massachusetts and Texas populations. These results suggest that sexual mating (macrocyst formation) is not likely to correlate with either genetic or geographical distance. To test this prediction, we performed 108 mating experiments and found no association between mating probability and genetic or geographical distance. CONCLUSIONS: D. giganteum isolates from across North America display little genetic variation, phylogeographic structure, and genetic differentiation among populations relative to the cryptic species observed within D. purpureum. Furthermore, variation that does exist does not predict the probability of mating among clones. These results have important implications for our understanding of speciation and social evolution in microbes.
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spelling pubmed-28246592010-02-19 Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum Mehdiabadi, Natasha J Kronforst, Marcus R Queller, David C Strassmann, Joan E BMC Evol Biol Research article BACKGROUND: Microorganisms are ubiquitous, yet we are only beginning to understand their diversity and population structure. Social amoebae (Dictyostelia) are a diverse group of unicellular eukaryotic microbes that display a unique social behaviour upon starvation in which cells congregate and then some die to help others survive and disperse. The genetic relationships among co-occurring cells have a major influence on the evolution of social traits and recent population genetic analysis found extensive genetic variation and possible cryptic speciation in one dictyostelid species (Dictyostelium purpureum). To further characterize the interplay among genetic variation, species boundaries, social behaviour, and reproductive isolation in the Dictyostelia, we conducted phylogenetic analyses and mating experiments with the geographically widespread social amoeba Dictyostelium giganteum. RESULTS: We sequenced approximately 4,000 basepairs of the nuclear ribosomal DNA from 24 isolates collected from Texas, Michigan, Massachusetts, Virginia, and Wisconsin and identified 16 unique haplotypes. Analyses of the sequence data revealed very little genetic differentiation among isolates and no clear evidence of phylogenetic structure, although there was evidence for some genetic differentiation between the Massachusetts and Texas populations. These results suggest that sexual mating (macrocyst formation) is not likely to correlate with either genetic or geographical distance. To test this prediction, we performed 108 mating experiments and found no association between mating probability and genetic or geographical distance. CONCLUSIONS: D. giganteum isolates from across North America display little genetic variation, phylogeographic structure, and genetic differentiation among populations relative to the cryptic species observed within D. purpureum. Furthermore, variation that does exist does not predict the probability of mating among clones. These results have important implications for our understanding of speciation and social evolution in microbes. BioMed Central 2010-01-20 /pmc/articles/PMC2824659/ /pubmed/20089169 http://dx.doi.org/10.1186/1471-2148-10-17 Text en Copyright ©2010 Mehdiabadi et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research article
Mehdiabadi, Natasha J
Kronforst, Marcus R
Queller, David C
Strassmann, Joan E
Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum
title Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum
title_full Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum
title_fullStr Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum
title_full_unstemmed Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum
title_short Phylogeography and sexual macrocyst formation in the social amoeba Dictyostelium giganteum
title_sort phylogeography and sexual macrocyst formation in the social amoeba dictyostelium giganteum
topic Research article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2824659/
https://www.ncbi.nlm.nih.gov/pubmed/20089169
http://dx.doi.org/10.1186/1471-2148-10-17
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