Phylogenomics of hyperthermophilic Archaea and Bacteria

2004 ◽  
Vol 32 (2) ◽  
pp. 175-178 ◽  
Author(s):  
H.-P. Klenk ◽  
M. Spitzer ◽  
T. Ochsenreiter ◽  
G. Fuellen

The location of hyperthermophilic organisms in the tree of life has been the source of many exciting discussions during the last two decades. It inspired not only novel hypotheses for the early evolution of the organisms, but also the isolation of many new species of Archaea and Bacteria from hot environments, as well as microbial genome sequencing and phylogenomic analyses. In view of the new wealth of genetic information generated from several analysed genomes of the hyperthermophiles, we can only conclude that the question of their exact phylogenetic location and evolutionary origin is presently as open as ever before.

Zootaxa ◽  
2017 ◽  
Vol 4329 (5) ◽  
pp. 477 ◽  
Author(s):  
CHIEN-HUI YANG ◽  
APPUKUTTANNAIR BIJU KUMAR ◽  
TIN-YAM CHAN

A new species of slipper lobster of the genus Petrarctus Holthuis, 2002 was discovered from southwestern India during a survey of deep sea crustaceans. The new species closely resembles P. veliger Holthuis, 2002 from the Andaman Sea and western Pacific but differs mainly in the color marking on abdominal somite I, having a relatively lower cardiac tooth but with better developed tubercles on the abdomen, as well as a differently shaped anterior part of the thoracic sternum. Molecular genetic analysis also confirms the distinct taxonomic status of the new species. To fix the identity of the type species of the genus, a neotype of P. rugosus (H. Milne Edwards, 1837) was selected from a recently collected Indian specimen with color and genetic information. 


2019 ◽  
Vol 36 (4) ◽  
pp. 757-765 ◽  
Author(s):  
Jürgen F H Strassert ◽  
Mahwash Jamy ◽  
Alexander P Mylnikov ◽  
Denis V Tikhonenkov ◽  
Fabien Burki

AbstractThe resolution of the broad-scale tree of eukaryotes is constantly improving, but the evolutionary origin of several major groups remains unknown. Resolving the phylogenetic position of these “orphan” groups is important, especially those that originated early in evolution, because they represent missing evolutionary links between established groups. Telonemia is one such orphan taxon for which little is known. The group is composed of molecularly diverse biflagellated protists, often prevalent although not abundant in aquatic environments. Telonemia has been hypothesized to represent a deeply diverging eukaryotic phylum but no consensus exists as to where it is placed in the tree. Here, we established cultures and report the phylogenomic analyses of three new transcriptome data sets for divergent telonemid lineages. All our phylogenetic reconstructions, based on 248 genes and using site-heterogeneous mixture models, robustly resolve the evolutionary origin of Telonemia as sister to the Sar supergroup. This grouping remains well supported when as few as 60% of the genes are randomly subsampled, thus is not sensitive to the sets of genes used but requires a minimal alignment length to recover enough phylogenetic signal. Telonemia occupies a crucial position in the tree to examine the origin of Sar, one of the most lineage-rich eukaryote supergroups. We propose the moniker “TSAR” to accommodate this new mega-assemblage in the phylogeny of eukaryotes.


PLoS ONE ◽  
2010 ◽  
Vol 5 (3) ◽  
pp. e9457 ◽  
Author(s):  
Jie Zhu ◽  
Edward L. Braun ◽  
Satomi Kohno ◽  
Monica Antenos ◽  
Eugene Y. Xu ◽  
...  

2021 ◽  
Author(s):  
Jadranka Rota ◽  
Victoria Gwendoline Twort ◽  
Andrea Chiocchio ◽  
Carlos Pena ◽  
Christopher W. Wheat ◽  
...  

The field of molecular phylogenetics is being revolutionised with next-generation sequencing technologies making it possible to sequence large numbers of genomes for non-model organisms ushering us into the era of phylogenomics. The current challenge is no longer how to get enough data, but rather how to analyse the data and how to assess the support for the inferred phylogeny. We focus on one of the largest animal groups on the planet - butterflies and moths (order Lepidoptera). We clearly demonstrate that there are unresolved issues in the inferred phylogenetic relationships of the major lineages, despite several recent phylogenomic studies of the group. We assess the potential causes and consequences of the conflicting phylogenetic hypotheses. With a dataset consisting of 331 protein-coding genes and the alignment length over 290 000 base pairs, including 200 taxa representing 81% of lepidopteran superfamilies, we compare phylogenetic hypotheses inferred from amino acid and nucleotide alignments. The resulting two phylogenies are discordant, especially with respect to the placement of the superfamily Gelechioidea, which is likely due to compositional bias of both the nucleotide and amino acid sequences. With a series of analyses, we dissect our dataset and demonstrate that there is sufficient phylogenetic signal to resolve much of the lepidopteran tree of life. Overall, the results from the nucleotide alignment are more robust to the various perturbations of the data that we carried out. However, the lack of support for much of the backbone within Ditrysia makes the current butterfly and moth tree of life still unresolved. We conclude that taxon sampling remains an issue even in phylogenomic analyses, and recommend that poorly sampled highly diverse groups, such as Gelechioidea in Lepidoptera, should receive extra attention in the future.


2018 ◽  
Author(s):  
Akanksha Pandey ◽  
Edward L. Braun

AbstractPhylogenomics has revolutionized the study of evolutionary relationships. However, genome-scale data have not been able to resolve all relationships in the tree of life. This could reflect the poor-fit of the models used to analyze heterogeneous datasets; that heterogeneity is likely to have many explanations. However, it seems reasonable to hypothesize that the different patterns of selection on proteins based on their structures might represent a source of heterogeneity. To test that hypothesis, we developed an efficient pipeline to divide phylogenomic datasets that comprise proteins into subsets based on secondary structure and relative solvent accessibility. We then tested whether amino acids in different structural environments had different signals for the deepest branches in the metazoan tree of life. Sites located in different structural environments did support distinct tree topologies. The most striking difference in phylogenetic signal reflected relative solvent accessibility; analyses of sites on the surface of proteins yielded a tree that placed ctenophores sister to all other animals whereas sites buried inside proteins yielded a tree with a sponge-ctenophore clade. These differences in phylogenetic signal were not ameliorated when we repeated our analyses using the site-heterogeneous CAT model, a mixture model that is often used for analyses of protein datasets. In fact, analyses using the CAT model actually resulted in rearrangements that are unlikely to represent evolutionary history. These results provide striking evidence that it will be necessary to achieve a better understanding the constraints due to protein structure to improve phylogenetic estimation.


Sign in / Sign up

Export Citation Format

Share Document