scholarly journals Comparative Genomics of the Archaea (Euryarchaeota): Evolution of Conserved Protein Families, the Stable Core, and the Variable Shell

1999 ◽  
Vol 9 (7) ◽  
pp. 608-628 ◽  
Author(s):  
Kira S. Makarova ◽  
L. Aravind ◽  
Michael Y. Galperin ◽  
Nick V. Grishin ◽  
Roman L. Tatusov ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Gene Families ◽  
Small Subset ◽  
Specific Gene ◽  
Genome Replication ◽  
Protein Families ◽  
Archaeal Protein ◽  
The Core ◽  
Stable Core

Comparative analysis of the protein sequences encoded in the four euryarchaeal species whose genomes have been sequenced completely (Methanococcus jannaschii, Methanobacterium thermoautotrophicum, Archaeoglobus fulgidus, andPyrococcus horikoshii) revealed 1326 orthologous sets, of which 543 are represented in all four species. The proteins that belong to these conserved euryarchaeal families comprise 31%–35% of the gene complement and may be considered the evolutionarily stable core of the archaeal genomes. The core gene set includes the great majority of genes coding for proteins involved in genome replication and expression, but only a relatively small subset of metabolic functions. For many gene families that are conserved in all euryarchaea, previously undetected orthologs in bacteria and eukaryotes were identified. A number of euryarchaeal synapomorphies (unique shared characters) were identified; these are protein families that possess sequence signatures or domain architectures that are conserved in all euryarchaea but are not found in bacteria or eukaryotes. In addition, euryarchaea-specific expansions of several protein and domain families were detected. In terms of their apparent phylogenetic affinities, the archaeal protein families split into bacterial and eukaryotic families. The majority of the proteins that have only eukaryotic orthologs or show the greatest similarity to their eukaryotic counterparts belong to the core set. The families of euryarchaeal genes that are conserved in only two or three species constitute a relatively mobile component of the genomes whose evolution should have involved multiple events of lineage-specific gene loss and horizontal gene transfer. Frequently these proteins have detectable orthologs only in bacteria or show the greatest similarity to the bacterial homologs, which might suggest a significant role of horizontal gene transfer from bacteria in the evolution of the euryarchaeota.

scholarly journals Plasmids Related to the Symbiotic Nitrogen Fixation Are Not Only Cooperated Functionally but Also May Have Evolved over a Time Span in Family Rhizobiaceae

2020 ◽  
Vol 12 (11) ◽  
pp. 2002-2014
Author(s):  
Ling-Ling Yang ◽  
Zhao Jiang ◽  
Yan Li ◽  
En-Tao Wang ◽  
Xiao-Yang Zhi
Keyword(s):  
Nitrogen Fixation ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Symbiotic Nitrogen Fixation ◽  
Gene Families ◽  
Time Span ◽  
Soil Conditions ◽  
Gene Gain ◽  
Nitrogen Fixing ◽  
Pan Genome

Abstract Rhizobia are soil bacteria capable of forming symbiotic nitrogen-fixing nodules associated with leguminous plants. In fast-growing legume-nodulating rhizobia, such as the species in the family Rhizobiaceae, the symbiotic plasmid is the main genetic basis for nitrogen-fixing symbiosis, and is susceptible to horizontal gene transfer. To further understand the symbioses evolution in Rhizobiaceae, we analyzed the pan-genome of this family based on 92 genomes of type/reference strains and reconstructed its phylogeny using a phylogenomics approach. Intriguingly, although the genetic expansion that occurred in chromosomal regions was the main reason for the high proportion of low-frequency flexible gene families in the pan-genome, gene gain events associated with accessory plasmids introduced more genes into the genomes of nitrogen-fixing species. For symbiotic plasmids, although horizontal gene transfer frequently occurred, transfer may be impeded by, such as, the host’s physical isolation and soil conditions, even among phylogenetically close species. During coevolution with leguminous hosts, the plasmid system, including accessory and symbiotic plasmids, may have evolved over a time span, and provided rhizobial species with the ability to adapt to various environmental conditions and helped them achieve nitrogen fixation. These findings provide new insights into the phylogeny of Rhizobiaceae and advance our understanding of the evolution of symbiotic nitrogen fixation.

scholarly journals Reconstructing the Phylogeny of Corynebacteriales while Accounting for Horizontal Gene Transfer

2020 ◽  
Vol 12 (4) ◽  
pp. 381-395
Author(s):  
Nilson Da Rocha Coimbra ◽  
Aristoteles Goes-Neto ◽  
Vasco Azevedo ◽  
Aïda Ouangraoua
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Phylogenetic Trees ◽  
Bacterial Species ◽  
Gene Tree ◽  
Gene Families ◽  
Common Mechanism ◽  
Species Trees ◽  
Bacterial Phylogeny ◽  
Homologous Genes

Abstract Horizontal gene transfer is a common mechanism in Bacteria that has contributed to the genomic content of existing organisms. Traditional methods for estimating bacterial phylogeny, however, assume only vertical inheritance in the evolution of homologous genes, which may result in errors in the estimated phylogenies. We present a new method for estimating bacterial phylogeny that accounts for the presence of genes acquired by horizontal gene transfer between genomes. The method identifies and corrects putative transferred genes in gene families, before applying a gene tree-based summary method to estimate bacterial species trees. The method was applied to estimate the phylogeny of the order Corynebacteriales, which is the largest clade in the phylum Actinobacteria. We report a collection of 14 phylogenetic trees on 360 Corynebacteriales genomes. All estimated trees display each genus as a monophyletic clade. The trees also display several relationships proposed by past studies, as well as new relevant relationships between and within the main genera of Corynebacteriales: Corynebacterium, Mycobacterium, Nocardia, Rhodococcus, and Gordonia. An implementation of the method in Python is available on GitHub at https://github.com/UdeS-CoBIUS/EXECT (last accessed April 2, 2020).

scholarly journals Human core duplicon gene families: game changers or game players?

2019 ◽  
Vol 18 (6) ◽  
pp. 402-411 ◽  
Author(s):  
Cemalettin Bekpen ◽  
Diethard Tautz
Keyword(s):  
Positive Selection ◽  
Protein Domains ◽  
Gene Families ◽  
Specific Gene ◽  
Gene Duplications ◽  
Human Lineage ◽  
Protein Families ◽  
Cellular Pathways ◽  
Human Specific

Abstract Illuminating the role of specific gene duplications within the human lineage can provide insights into human-specific adaptations. The so-called human core duplicon gene families have received particular attention in this respect, due to special features, such as expansion along single chromosomes, newly acquired protein domains and signatures of positive selection. Here, we summarize the data available for 10 such families and include some new analyses. A picture emerges that suggests broad functions for these protein families, possibly through modification of core cellular pathways. Still, more dedicated studies are required to elucidate the function of core-duplicons gene families and how they have shaped adaptations and evolution of humans.

scholarly journals De Novo Gene Birth, Horizontal Gene Transfer, and Gene Duplication as Sources of New Gene Families Associated with the Origin of Symbiosis in Amanita

2020 ◽  
Vol 12 (11) ◽  
pp. 2168-2182
Author(s):  
Yen-Wen Wang ◽  
Jaqueline Hess ◽  
Jason C Slot ◽  
Anne Pringle
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Gene Duplication ◽  
De Novo ◽  
Gene Families ◽  
Negative Regulator ◽  
Orphan Gene ◽  
Unique Gene ◽  
De Novo Gene ◽  
New Gene

Abstract By introducing novel capacities and functions, new genes and gene families may play a crucial role in ecological transitions. Mechanisms generating new gene families include de novo gene birth, horizontal gene transfer, and neofunctionalization following a duplication event. The ectomycorrhizal (ECM) symbiosis is a ubiquitous mutualism and the association has evolved repeatedly and independently many times among the fungi, but the evolutionary dynamics enabling its emergence remain elusive. We developed a phylogenetic workflow to first understand if gene families unique to ECM Amanita fungi and absent from closely related asymbiotic species are functionally relevant to the symbiosis, and then to systematically infer their origins. We identified 109 gene families unique to ECM Amanita species. Genes belonging to unique gene families are under strong purifying selection and are upregulated during symbiosis, compared with genes of conserved or orphan gene families. The origins of seven of the unique gene families are strongly supported as either de novo gene birth (two gene families), horizontal gene transfer (four), or gene duplication (one). An additional 34 families appear new because of their selective retention within symbiotic species. Among the 109 unique gene families, the most upregulated gene in symbiotic cultures encodes a 1-aminocyclopropane-1-carboxylate deaminase, an enzyme capable of downregulating the synthesis of the plant hormone ethylene, a common negative regulator of plant-microbial mutualisms.

scholarly journals Phylogenetic analyses suggest centipede venom arsenals were repeatedly stocked by horizontal gene transfer

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Eivind A. B. Undheim ◽  
Ronald A. Jenner
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Phylogenetic Analyses ◽  
Gene Families ◽  
Venom Gland ◽  
Bacterial Gene ◽  
Multiple Gene ◽  
Genomic Analyses ◽  
Endogenous Proteins ◽  
Animal Venoms

AbstractVenoms have evolved over a hundred times in animals. Venom toxins are thought to evolve mostly by recruitment of endogenous proteins with physiological functions. Here we report phylogenetic analyses of venom proteome-annotated venom gland transcriptome data, assisted by genomic analyses, to show that centipede venoms have recruited at least five gene families from bacterial and fungal donors, involving at least eight horizontal gene transfer events. These results establish centipedes as currently the only known animals with venoms used in predation and defence that contain multiple gene families derived from horizontal gene transfer. The results also provide the first evidence for the implication of horizontal gene transfer in the evolutionary origin of venom in an animal lineage. Three of the bacterial gene families encode virulence factors, suggesting that horizontal gene transfer can provide a fast track channel for the evolution of novelty by the exaptation of bacterial weapons into animal venoms.

scholarly journals Horizontal gene transfer among rhizobia of the Core Cape Subregion of southern Africa

2018 ◽  
Vol 118 ◽  
pp. 342-352 ◽  
Author(s):  
M.N. Dludlu ◽  
S.B.M. Chimphango ◽  
G. Walker ◽  
C.H. Stirton ◽  
A.M. Muasya
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Southern Africa ◽  
The Core

scholarly journals Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade

2015 ◽  
Vol 112 (52) ◽  
pp. 15976-15981 ◽  
Author(s):  
Thomas C. Boothby ◽  
Jennifer R. Tenlen ◽  
Frank W. Smith ◽  
Jeremy R. Wang ◽  
Kiera A. Patanella ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Large Fraction ◽  
Draft Genome ◽  
Gene Families ◽  
Extreme Conditions ◽  
Physical Linkage ◽  
Foreign Genes ◽  
Direct Confirmation

Horizontal gene transfer (HGT), or the transfer of genes between species, has been recognized recently as more pervasive than previously suspected. Here, we report evidence for an unprecedented degree of HGT into an animal genome, based on a draft genome of a tardigrade, Hypsibius dujardini. Tardigrades are microscopic eight-legged animals that are famous for their ability to survive extreme conditions. Genome sequencing, direct confirmation of physical linkage, and phylogenetic analysis revealed that a large fraction of the H. dujardini genome is derived from diverse bacteria as well as plants, fungi, and Archaea. We estimate that approximately one-sixth of tardigrade genes entered by HGT, nearly double the fraction found in the most extreme cases of HGT into animals known to date. Foreign genes have supplemented, expanded, and even replaced some metazoan gene families within the tardigrade genome. Our results demonstrate that an unexpectedly large fraction of an animal genome can be derived from foreign sources. We speculate that animals that can survive extremes may be particularly prone to acquiring foreign genes.

scholarly journals Evolution of Aminoacyl-tRNA Synthetases—Analysis of Unique Domain Architectures and Phylogenetic Trees Reveals a Complex History of Horizontal Gene Transfer Events

1999 ◽  
Vol 9 (8) ◽  
pp. 689-710 ◽  
Author(s):  
Yuri I. Wolf ◽  
L. Aravind ◽  
Nick V. Grishin ◽  
Eugene V. Koonin
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Phylogenetic Trees ◽  
Domain Architecture ◽  
Specific Gene ◽  
Trna Synthetases ◽  
Aminoacyl Trna Synthetases ◽  
Eukaryotic Genes ◽  
Multiple Alignments

Phylogenetic analysis of aminoacyl-tRNA synthetases (aaRSs) of all 20 specificities from completely sequenced bacterial, archaeal, and eukaryotic genomes reveals a complex evolutionary picture. Detailed examination of the domain architecture of aaRSs using sequence profile searches delineated a network of partially conserved domains that is even more elaborate than previously suspected. Several unexpected evolutionary connections were identified, including the apparent origin of the β-subunit of bacterial GlyRS from the HD superfamily of hydrolases, a domain shared by bacterial AspRS and the B subunit of archaeal glutamyl-tRNA amidotransferases, and another previously undetected domain that is conserved in a subset of ThrRS, guanosine polyphosphate hydrolases and synthetases, and a family of GTPases. Comparison of domain architectures and multiple alignments resulted in the delineation of synapomorphies—shared derived characters, such as extra domains or inserts—for most of the aaRSs specificities. These synapomorphies partition sets of aaRSs with the same specificity into two or more distinct and apparently monophyletic groups. In conjunction with cluster analysis and a modification of the midpoint-rooting procedure, this partitioning was used to infer the likely root position in phylogenetic trees. The topologies of the resulting rooted trees for most of the aaRSs specificities are compatible with the evolutionary “standard model” whereby the earliest radiation event separated bacteria from the common ancestor of archaea and eukaryotes as opposed to the two other possible evolutionary scenarios for the three major divisions of life. For almost all aaRSs specificities, however, this simple scheme is confounded by displacement of some of the bacterial aaRSs by their eukaryotic or, less frequently, archaeal counterparts. Displacement of ancestral eukaryotic aaRS genes by bacterial ones, presumably of mitochondrial origin, was observed for three aaRSs. In contrast, there was no convincing evidence of displacement of archaeal aaRSs by bacterial ones. Displacement of aaRS genes by eukaryotic counterparts is most common among parasitic and symbiotic bacteria, particularly the spirochaetes, in which 10 of the 19 aaRSs seem to have been displaced by the respective eukaryotic genes and two by the archaeal counterpart. Unlike the primary radiation events between the three main divisions of life, that were readily traceable through the phylogenetic analysis of aaRSs, no consistent large-scale bacterial phylogeny could be established. In part, this may be due to additional gene displacement events among bacterial lineages. Argument is presented that, although lineage-specific gene loss might have contributed to the evolution of some of the aaRSs, this is not a viable alternative to horizontal gene transfer as the principal evolutionary phenomenon in this gene class.[Complete multiple alignments of all aaRSs from complete genomes as well as the alignments of conserved regions used for phylogenetic tree construction are available at ftp://ncbi.nlm.nih.gov/pub/koonin/aaRS]

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