scholarly journals Gene duplications trace mitochondria to the onset of eukaryote complexity

2019 ◽  
Author(s):  
Fernando D. K. Tria ◽  
Julia Brückner ◽  
Josip Skejo ◽  
Joana C. Xavier ◽  
Verena Zimorski ◽  
...  
Keyword(s):  
Lipid Synthesis ◽  
Evolutionary Process ◽  
Eukaryotic Cell ◽  
Evolutionary Significance ◽  
Gene Duplications ◽  
Gene Trees ◽  
Sequence Of Events ◽  
Mitochondrial Functions ◽  
Duplication Events ◽  
Host Lineage

AbstractThe last eukaryote common ancestor (LECA) lived 1.6 billion years ago1,2. It possessed nuclei, sex, an endomembrane system, mitochondria, and all key traits that make eukaryotic cells more complex than their prokaryotic ancestors2–6. The closest known relatives of the host lineage that acquired the mitochondrion are, however, small obligately symbiotic archaea that lack any semblance of eukaryotic cell complexity7. Although the steep evolutionary grade separating prokaryotes from eukaryotes increasingly implicates mitochondrial symbiosis at eukaryote origin4,7, the timing and evolutionary significance of mitochondrial origin remains debated. Gradualist theories contend that eukaryotes arose from archaea by slow accumulation of eukaryotic traits8–10 with mitochondria arriving late11, while symbiotic theories have it that mitochondria initiated the onset of eukaryote complexity in a non-nucleated archaeal host7 by gene transfers from the organelle4,12–14. The evolutionary process leading to LECA should be recorded in its gene duplications. Among 163,545 duplications in 24,571 gene trees spanning 150 sequenced eukaryotic genomes we identified 713 gene duplication events that occurred in LECA. LECA’s bacterially derived genes were duplicated more frequently than archaeal derived or eukaryote specific genes, reflecting the serial copying15,16 of genes from the mitochondrial endosymbiont to the archaeal host’s chromosomes prior to the onset of eukaryote genome complexity. Bacterial derived genes for mitochondrial functions, lipid synthesis, biosynthesis, as well as core carbon and energy metabolism in LECA were duplicated more often than archaeal derived genes and even more often than eukaryote-specific inventions for endomembrane, cytoskeletal or cell cycle functions. Gene duplications record the sequence of events at LECA’s origin and indicate that recurrent gene transfer from a resident mitochondrial endosymbiont preceded the onset of eukaryotic cellular complexity.

scholarly journals Conflict and cooperation in eukaryogenesis: implications for the timing of endosymbiosis and the evolution of sex

2015 ◽  
Author(s):  
Arunas L Radzvilavicius ◽  
Neil W Blackstone
Keyword(s):  
Cell Fusion ◽  
Mitochondrial Gene ◽  
Evolutionary Process ◽  
Eukaryotic Cell ◽  
Evolutionary Transition ◽  
Evolutionary Transitions ◽  
Conflict And Cooperation ◽  
Conflict Mediation ◽  
Considerable Debate ◽  
History Of

The complex eukaryotic cell is a result of an ancient endosymbiosis and one of the major evolutionary transitions. The timing of key eukaryotic innovations relative to the acquisition of mitochondria remains subject to considerable debate, yet the evolutionary process itself might constrain the order of these events. Endosymbiosis entailed levels-of-selection conflicts, and mechanisms of conflict mediation had to evolve for eukaryogenesis to proceed. The initial mechanisms of conflict mediation were based on the pathways inherited from prokaryotic symbionts and led to metabolic homeostasis in the eukaryotic cell, while later mechanisms (e.g., mitochondrial gene transfer) contributed to the expansion of the eukaryotic genome. Perhaps the greatest opportunity for conflict arose with the emergence of sex involving whole-cell fusion. While early evolution of cell fusion may have affected symbiont acquisition, sex together with the competitive symbiont behaviour would have destabilised the emerging higher-level unit. Cytoplasmic mixing, on the other hand, would have been beneficial for selfish endosymbionts, capable of using their own metabolism to manipulate the life history of the host. Given the results of our mathematical modelling, we argue that sex represents a rather late proto- eukaryotic innovation, allowing for the growth of the chimeric nucleus and contributing to the successful completion of the evolutionary transition.

scholarly journals Origin and Evolution of the Neuroendocrine Control of Reproduction in Vertebrates, With Special Focus on Genome and Gene Duplications

2020 ◽  
Vol 100 (2) ◽  
pp. 869-943 ◽  
Author(s):  
Sylvie Dufour ◽  
Bruno Quérat ◽  
Hervé Tostivint ◽  
Catherine Pasqualini ◽  
Hubert Vaudry ◽  
...  
Keyword(s):  
Special Focus ◽  
Gene Duplications ◽  
Vertebrate Lineage ◽  
Neuroendocrine Control ◽  
Origin And Evolution ◽  
Large Panel ◽  
Gonadotropic Axis ◽  
Duplication Events ◽  
The Brain ◽  
Hypophysial Portal

In humans, as in the other mammals, the neuroendocrine control of reproduction is ensured by the brain-pituitary gonadotropic axis. Multiple internal and environmental cues are integrated via brain neuronal networks, ultimately leading to the modulation of the activity of gonadotropin-releasing hormone (GnRH) neurons. The decapeptide GnRH is released into the hypothalamic-hypophysial portal blood system and stimulates the production of pituitary glycoprotein hormones, the two gonadotropins luteinizing hormone and follicle-stimulating hormone. A novel actor, the neuropeptide kisspeptin, acting upstream of GnRH, has attracted increasing attention in recent years. Other neuropeptides, such as gonadotropin-inhibiting hormone/RF-amide related peptide, and other members of the RF-amide peptide superfamily, as well as various nonpeptidic neuromediators such as dopamine and serotonin also provide a large panel of stimulatory or inhibitory regulators. This paper addresses the origin and evolution of the vertebrate gonadotropic axis. Brain-pituitary neuroendocrine axes are typical of vertebrates, the pituitary gland, mediator and amplifier of brain control on peripheral organs, being a vertebrate innovation. The paper reviews, from molecular and functional perspectives, the evolution across vertebrate radiation of some key actors of the vertebrate neuroendocrine control of reproduction and traces back their origin along the vertebrate lineage and in other metazoa before the emergence of vertebrates. A focus is given on how gene duplications, resulting from either local events or from whole genome duplication events, and followed by paralogous gene loss or conservation, might have shaped the evolutionary scenarios of current families of key actors of the gonadotropic axis.

scholarly journals On the systematics and the phylogenetic position of the poorly known, montane dragon-lizard species Pseudocalotes austeniana (Annandale, 1908) (Squamata, Agamidae, Draconinae)

2021 ◽  
Vol 5 (1) ◽  
pp. 141-150
Author(s):  
Gaurang G. Gowande ◽  
Harshal S. Bhosale ◽  
Pushkar U. Phansalkar ◽  
Mandar Sawant ◽  
Zeeshan A. Mirza
Keyword(s):  
Molecular Phylogenetics ◽  
Sequence Data ◽  
Systematic Position ◽  
Sensu Stricto ◽  
Evolutionary Significance ◽  
Phylogenetic Position ◽  
Gene Trees ◽  
Lizard Species ◽  
Molecular Sequence Data ◽  
Molecular Sequence

The montane agamid species Pseudocalotes austeniana has had a complicated taxonomic history, as the species was initially described as a member of the genus Salea Gray, 1845. Later, the species was placed in a monotypic genus Mictopholis Smith, 1935, which was erected only to include this species; however, the species was later on transferred to the genus Pseudocalotes Fitzinger, 1843, owing to the morphological similarities, and lack of strong characters to diagnose the genus Mictopholis. Nonetheless, its precise phylogenetic and systematic position has remained unresolved due to the lack of molecular sequence data. During a herpetological expedition to Arunachal Pradesh, specimens of P. austeniana were collected from the hills near the type locality. The mitochondrial 16S rRNA, ND2 and ND4, and the nuclear RAG1 regions were subjected to molecular phylogenetics. Maximum Likelihood and Bayesian Inference gene trees revealed that P. austeniana is a member of the subfamily Draconinae. The analyses showed that the genus Pseudocalotes is polyphyletic, and P. austeniana was embedded within the genus Japalura Gray, 1853 sensu stricto. We here, thus, propose to transfer the species P. austeniana to the genus Japlaura, as Japalura austenianacomb. nov. Biogeographic and evolutionary significance of the findings are discussed.

scholarly journals Patterns of gene evolution following duplications and speciations in vertebrates

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8813 ◽  
Author(s):  
Kyle T. David ◽  
Jamie R. Oaks ◽  
Kenneth M. Halanych
Keyword(s):  
Gene Duplication ◽  
Gene Evolution ◽  
Strong Support ◽  
Duplication Event ◽  
Gene Trees ◽  
Loss Of Function ◽  
Eukaryotic Genes ◽  
Gene Copies ◽  
Duplication Events ◽  
And Function

Background Eukaryotic genes typically form independent evolutionary lineages through either speciation or gene duplication events. Generally, gene copies resulting from speciation events (orthologs) are expected to maintain similarity over time with regard to sequence, structure and function. After a duplication event, however, resulting gene copies (paralogs) may experience a broader set of possible fates, including partial (subfunctionalization) or complete loss of function, as well as gain of new function (neofunctionalization). This assumption, known as the Ortholog Conjecture, is prevalent throughout molecular biology and notably plays an important role in many functional annotation methods. Unfortunately, studies that explicitly compare evolutionary processes between speciation and duplication events are rare and conflicting. Methods To provide an empirical assessment of ortholog/paralog evolution, we estimated ratios of nonsynonymous to synonymous substitutions (ω = dN/dS) for 251,044 lineages in 6,244 gene trees across 77 vertebrate taxa. Results Overall, we found ω to be more similar between lineages descended from speciation events (p < 0.001) than lineages descended from duplication events, providing strong support for the Ortholog Conjecture. The asymmetry in ω following duplication events appears to be largely driven by an increase along one of the paralogous lineages, while the other remains similar to the parent. This trend is commonly associated with neofunctionalization, suggesting that gene duplication is a significant mechanism for generating novel gene functions.

scholarly journals GeneSeqToFamily: the Ensembl Compara GeneTrees pipeline as a Galaxy workflow

2016 ◽  
Author(s):  
Anil S. Thanki ◽  
Nicola Soranzo ◽  
Wilfried Haerty ◽  
Robert P. Davey
Keyword(s):  
Gene Duplication ◽  
Structural Changes ◽  
Gene Families ◽  
Vital Role ◽  
Software Project ◽  
Command Line ◽  
Gene Trees ◽  
Ancestral Gene ◽  
The Galaxy ◽  
Duplication Events

AbstractBackgroundGene duplication is a major factor contributing to evolutionary novelty, and the contraction or expansion of gene families has often been associated with morphological, physiological and environmental adaptations. The study of homologous genes helps us to understand the evolution of gene families. It plays a vital role in finding ancestral gene duplication events as well as identifying genes that have diverged from a common ancestor under positive selection. There are various tools available, such as MSOAR, OrthoMCL and HomoloGene, to identify gene families and visualise syntenic information between species, providing an overview of syntenic regions evolution at the family level. Unfortunately, none of them provide information about structural changes within genes, such as the conservation of ancestral exon boundaries amongst multiple genomes. The Ensembl GeneTrees computational pipeline generates gene trees based on coding sequences and provides details about exon conservation, and is used in the Ensembl Compara project to discover gene families.FindingsA certain amount of expertise is required to configure and run the Ensembl Compara GeneTrees pipeline via command line. Therefore, we have converted the command line Ensembl Compara GeneTrees pipeline into a Galaxy workflow, called GeneSeqToFamily, and provided additional functionality. This workflow uses existing tools from the Galaxy ToolShed, as well as providing additional wrappers and tools that are required to run the workflow.ConclusionsGeneSeqToFamily represents the Ensembl Compara pipeline as a set of interconnected Galaxy tools, so they can be run interactively within the Galaxy’s user-friendly workflow environment while still providing the flexibility to tailor the analysis by changing configurations and tools if necessary. Additional tools allow users to subsequently visualise the gene families produced by the workflow, using the Aequatus.js interactive tool, which has been developed as part of the Aequatus software project.

scholarly journals Gene Loss and Evolution of the Plastome

2019 ◽  
Author(s):  
Tapan Kumar Mohanta ◽  
Awdhesh Kumar Mishra ◽  
Adil Khan ◽  
Abeer Hashem ◽  
Elsayed Fathi Abd_Allah ◽  
...  
Keyword(s):  
Chloroplast Genome ◽  
Dna Sequences ◽  
Nuclear Genome ◽  
Evolutionary Process ◽  
Life Forms ◽  
Evolutionary Analysis ◽  
Origin And Evolution ◽  
The Earth ◽  
Chloroplast Genomes ◽  
Duplication Events

AbstractChloroplasts are unique organelles within the plant cells and are responsible for sustaining life forms on the earth due to their ability to conduct photosynthesis. Multiple functional genes within the chloroplast are responsible for a variety of metabolic processes that occur in the chloroplast. Considering its fundamental role in sustaining life on the earth, it is important to identify the level of diversity present in the chloroplast genome, what genes and genomic content have been lost, what genes have been transferred to the nuclear genome, duplication events, and the overall origin and evolution of the chloroplast genome. Our analysis of 2511 chloroplast genomes indicated that the genome size and number of coding DNA sequences (CDS) in the chloroplasts genome of algae are higher relative to other lineages. Approximately 10.31% of the examined species have lost the inverted repeats (IR) in the chloroplast genome that span across all the lineages. Genome-wide analyses revealed the loss of the Rbcl gene in parasitic and heterotrophic plants occurred approximately 56 Ma ago. PsaM, Psb30, ChlB, ChlL, ChlN, and Rpl21 were found to be characteristic signature genes of the chloroplast genome of algae, bryophytes, pteridophytes, and gymnosperms; however, none of these genes were found in the angiosperm or magnoliid lineage which appeared to have lost them approximately 203–156 Ma ago. A variety of chloroplast-encoded genes were lost across different species lineages throughout the evolutionary process. The Rpl20 gene, however, was found to be the most stable and intact gene in the chloroplast genome and was not lost in any of the analyzed species, suggesting that it is a signature gene of the plastome. Our evolutionary analysis indicated that chloroplast genomes evolved from multiple common ancestors ~1293 Ma ago and have undergone vivid recombination events across different taxonomic lineages.

scholarly journals Aequatus: An open-source homology browser

2016 ◽  
Author(s):  
Anil S. Thanki ◽  
Nicola Soranzo ◽  
Javier Herrero ◽  
Wilfried Haerty ◽  
Robert P. Davey
Keyword(s):  
Open Source ◽  
Structural Changes ◽  
Gene Tree ◽  
Purifying Selection ◽  
Gene Families ◽  
Gene Trees ◽  
Ancestral Gene ◽  
Link Type ◽  
The Galaxy ◽  
Duplication Events

AbstractBackgroundPhylogenetic information inferred from the study of homologous genes helps us to understand the evolution of genes and gene families, including the identification of ancestral gene duplication events as well as regions under positive or purifying selection within lineages. Gene family and orthogroup characterisation enables the identification of syntenic blocks, which can then be visualised with various tools. Unfortunately, currently available tools display only an overview of syntenic regions as a whole, limited to the gene level, and none provide further details about structural changes within genes, such as the conservation of ancestral exon boundaries amongst multiple genomes.FindingsWe present Aequatus, a standalone web-based tool that provides an in-depth view of gene structure across gene families, with various options to render and filter visualisations. It relies on pre-calculated alignment and gene feature information typically held in, but not limited to, the Ensembl Compara and Core databases. We also offer Aequatus.js, a reusable JavaScript module that fulfils the visualisation aspects of Aequatus, available within the Galaxy web platform as a visualisation plugin, which can be used to visualise gene trees generated by the GeneSeqToFamily workflow.AvailabilityAequatus is an open-source tool freely available to download under the MIT license at https://github.com/TGAC/Aequatus. A demo server is available at http://aequatus.earlham.ac.uk/. A publicly available instance of the GeneSeqToFamily workflow to generate gene tree information and visualise it using Aequatus is available on the Galaxy EU server at https://[email protected] and [email protected]

scholarly journals Gene Loss and Evolution of the Plastome

2020 ◽  
Author(s):  
Tapan Kumar Mohanta ◽  
Adil Khan ◽  
Abdul Latif Khan ◽  
Abeer Hashem ◽  
Elsayed Fathi Abd_Allah ◽  
...  
Keyword(s):  
Chloroplast Genome ◽  
Nuclear Genome ◽  
Evolutionary Process ◽  
Life Forms ◽  
Inverted Repeats ◽  
Rbcl Gene ◽  
Evolutionary Analysis ◽  
Origin And Evolution ◽  
Chloroplast Genomes ◽  
Duplication Events

Abstract Chloroplasts are unique organelles within plant cells and are ultimately responsible for sustaining life forms on the earth due to their ability to conduct photosynthesis. Multiple functional genes within the chloroplast are responsible for a variety of metabolic processes that occur in the chloroplast. Considering its fundamental role in sustaining life on earth, it is important to identify the level of diversity present in the chloroplast genome, what genes and genomic content have been lost, what genes have been transferred to the nuclear genome, duplication events, and the overall origin and evolution of the chloroplast genome. Our analysis of 2511 chloroplast genomes indicated that the genome size and number of CDS in the chloroplasts of algae are higher relative to other lineages. Approximately 10.31% of the examined species have lost the inverted repeats (IR) that span across the lineages that comprise algae, bryophytes, pteridophytes, gymnosperm, angiosperms, magnoliids, and protists. Genome-wide analyses revealed that the loss of the Rbcl gene in parasitic and heterotrophic plant species occurred approximately 56 Ma ago. PsaM, Psb30, ChlB, ChlL, ChlN, and Rpl21 were found to be characteristic signature genes of chloroplast genome of algae, bryophytes, pteridophytes, and gymnosperms; while none of these genes were found in the angiosperm or magnoliid lineage which appeared to have lost them approximately 203-156 Ma ago. A variety of chloroplast encoding genes were lost across different species lineages throughout the evolutionary process. The Rpl20 gene, however, was found to be the most stable and intact gene in the chloroplast genome and was not lost in any of the analysed species; suggesting that it is a signature gene of the plastome. Our evolutionary analysis indicated that chloroplast genomes evolved from multiple common ancestors ~1293 Ma ago and have undergone vivid recombination events across different taxonomic lineages. Additionally, our findings support the hypothesis that these recombination events are the most probable cause behind the dynamic loss of chloroplast genes and inverted repeats in different species.

scholarly journals Genome-Wide identification and Analysis of the AP2/ERF Gene Family in Fragaria vesca

2019 ◽  
Author(s):  
Zekun Li ◽  
Yanhong Hong ◽  
Changmei Chen ◽  
Zhennan Wang ◽  
Aiying Zheng ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Expression Profiles ◽  
Critical Role ◽  
Evolutionary Relationship ◽  
Evolutionary Process ◽  
Promoter Sequence ◽  
Good Opportunity ◽  
Genome Wide ◽  
Duplication Events ◽  
Erf Family

Abstract Background: The AP2/ERF superfamily consists of primary transcription factors in plants that play a critical role in numerous aspects of various physiological stages and responses to stress stimuli. Nevertheless, there is little information related to AP2/ERF in strawberry, an important perennial fruit and model plant for horticulture. Results: In this study, 117 AP2/ERF genes were identified in strawberry and were grouped into four types of genes, AP2 (17), ERF (94), RAV (5) as well as soloist (1), according to the gene structure, phylogenetic tree and conserved domains. The duplication events and synteny analysis combination of genes offered a good opportunity to understand the evolutionary process of the FvAP2/ERF family. Moreover, identified orthologous genes and expression profiles of genes across various tissue, developmental stages and different treatments predicted potential functions of some AP2/ERF genes in strawberry. Conclusions: In this study, 117 genes were identified in the AP2/ERF family of strawberry, and their structure, chromosomes location, evolutionary relationship, promoter sequence and expression profile were investigated. Our findings provide valuable clues to gain better insights into each FvAP2/ERF gene under different types of biological developments and in response to stressors.

scholarly journals Evolutionary significance of amino acid permease transporters in 17 plants from Chlorophyta to Angiospermae

2020 ◽  
Author(s):  
Chao Zhang ◽  
Nana Kong ◽  
Minxuan Cao ◽  
Dongdong Wang ◽  
Yue Chen ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Evolutionary Significance ◽  
Future Research ◽  
Amino Acid Permease ◽  
Group I ◽  
New Findings ◽  
Duplication Events ◽  
Living Organisms ◽  
Clade 1

Abstract Background: Nitrogen is an indispensable nutrient for plant growth. It is used and transported in the form of amino acids in living organisms. Transporting amino acids to various parts of plants requires relevant transport proteins, such as amino acid permeases (AAPs), which were our focus in this study.Results: We found that 5 AAP genes were present in Chlorophyte species and more AAP genes were predicted in Bryophyta and Lycophytes. Two main groups were defined and group I comprised 5 clades. Our phylogenetic analysis indicated that the origin of clades 2, 3, and 4 is Gymnospermae and that these clades are closely related. The members of clade 1 included Chlorophyta to Gymnospermae. Group II, as a new branch consisting of non-seed plants, is first proposed in our research. Our results also indicated that the AAP family was already present in Chlorophyta and then expanded accompanying the development of vasculature. Concurrently, the AAP family experienced multiple duplication events that promoted the generation of new functions and differentiation of sub-functions.Conclusions: Our findings suggest that the AAP gene originated in Chlorophyta, and some non-seed AAP genes clustered in one group. A second group, which contained plants of all evolutionary stages, indicated the evolution of AAPs. These new findings can be used to guide future research.

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