| 1. |
- Romeralo, Maria, et al.
(author)
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A Fully Resolved Phylogeny of the Social Amoebas (Dictyostelia) Based on Combined SSU and ITS rDNA Sequences
- 2010
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In: Protist. - : Elsevier BV. - 1434-4610 .- 1618-0941. ; 161:4, s. 539-548
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Journal article (peer-reviewed)abstract
- The dictyostelids possess a complex life cycle including aggregative and multicellular stages. They also include one of the most widely studied protistan model organisms, Dictyostelium discoideum. The current molecular phylogeny of dictyostelids is based largely on SSU (18S) rDNA sequences and shows a deep taxon consisting of four major groups, none of which correspond to the three traditional morphologically-defined genera. However, due to the generally slowly evolving nature of SSU rDNA, these data fail to resolve the majority of branches within the four groups. Given the highly morphologically mixed nature of the dictyostelid groups, it is important to resolve relationships within them. We have determined sequences for the internal transcribed spacers (ITS) of rDNA for nearly all species in the original dictyostelid global phylogeny. Phylogenetic analyses of these data, in combination with the previously determined SSUr DNA sequences, confidently resolve nearly all branches in the tree. This now fully resolved phylogeny confirms the utility of ITS for dictyostelid systematics and lays the ground work for further evolutionary study of the group. (c) 2010 Elsevier GmbH. All rights reserved.
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| 2. |
- Romeralo, Maria, et al.
(author)
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Population structure of the social amoeba Dictyostelium rosarium based on rDNA
- 2010
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In: Fungal Ecology. - : Elsevier BV. - 1754-5048. ; 3:4, s. 379-385
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Journal article (peer-reviewed)abstract
- The extent of genetic variation that occurs among isolates of the social amoeba Dictyostelium rosarium obtained from a number of widely separated geographical localities around the world was investigated. Population diversity of D. rosarium was analyzed using sequences from the rDNA internal transcribed spacer (ITS1 and ITS2) and the 5.8S gene of 24 different isolates. Sequence analysis revealed little variation in the approximately 900 base pair ITS region of D. rosarium. No significant sequence variation was detected among the isolates examined, which suggests that the ITS region is extremely conserved in this species and also that D. rosarium morphotypes constitute a well-defined genetic entity (i.e., species).
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| 3. |
- Romeralo, Maria, et al.
(author)
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Two new species of dictyostelid cellular slime molds from Alaska
- 2010
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In: Mycologia. - : Informa UK Limited. - 0027-5514 .- 1557-2536. ; 102:3, s. 588-595
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Journal article (peer-reviewed)abstract
- In sampling soils to survey dictyostelid cellular slime molds in Alaska we encountered two groups of isolates that have morphologies that differ from any previously described species within their group. We sequenced the nuclear small subunit ribosomal RNA gene (SSU rDNA) of selected isolates from the two groups and found sequences from both groups to be distinct from all previously described dictyostelid sequences. Phylogenetic analyses place one novel species in dictyostelid Group 2 and the other in Group 4 (Schaap et al. 2006). In this paper we formally describe as new these two species of cellular slime molds, Dictyostelium ammophilum sp. nov. and Dictyostelium borealesp. nov., based on the combination of morphological and molecular characters.
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