scholarly journals Portiera Gets Wild: Genome Instability Provides Insights into the Evolution of Both Whiteflies and Their Endosymbionts

2020 ◽  
Vol 12 (11) ◽  
pp. 2107-2124
Author(s):  
Diego Santos-Garcia ◽  
Natividad Mestre-Rincon ◽  
David Ouvrard ◽  
Einat Zchori-Fein ◽  
Shai Morin
Keyword(s):  
Evolutionary History ◽  
Common Ancestor ◽  
Genome Instability ◽  
Rare Event ◽  
Essential Amino Acids ◽  
Phylogenetic Framework ◽  
The Common ◽  
Phloem Feeding ◽  
New Framework ◽  
Time Point

Abstract Whiteflies (Hemiptera: Sternorrhyncha: Aleyrodidae) are a superfamily of small phloem-feeding insects. They rely on their primary endosymbionts "Candidatus Portiera aleyrodidarum" to produce essential amino acids not present in their diet. Portiera has been codiverging with whiteflies since their origin and therefore reflects its host’s evolutionary history. Like in most primary endosymbionts, the genome of Portiera stays stable across the Aleyrodidae superfamily after millions of years of codivergence. However, Portiera of the whitefly Bemisia tabaci has lost the ancestral genome order, reflecting a rare event in the endosymbiont evolution: the appearance of genome instability. To gain a better understanding of Portiera genome evolution, identify the time point in which genome instability appeared and contribute to the reconstruction of whitefly phylogeny, we developed a new phylogenetic framework. It targeted five Portiera genes and determined the presence of the DNA polymerase proofreading subunit (dnaQ) gene, previously associated with genome instability, and two alternative gene rearrangements. Our results indicated that Portiera gene sequences provide a robust tool for studying intergenera phylogenetic relationships in whiteflies. Using these new framework, we found that whitefly species from the Singhiella, Aleurolobus, and Bemisia genera form a monophyletic tribe, the Aleurolobini, and that their Portiera exhibit genome instability. This instability likely arose once in the common ancestor of the Aleurolobini tribe (at least 70 Ma), drawing a link between the appearance of genome instability in Portiera and the switch from multibacteriocyte to a single-bacteriocyte mode of inheritance in this tribe.

scholarly journals Portiera gives new clues on the evolutionary history of whiteflies

2020 ◽  
Author(s):  
D. Santos-Garcia ◽  
N. Mestre-Rincon ◽  
D. Ouvrard ◽  
E. Zchori-Fein ◽  
S. Morin
Keyword(s):  
Evolutionary History ◽  
Target Genes ◽  
Common Ancestor ◽  
Genome Instability ◽  
Phylogenetic Reconstructions ◽  
Stability And Instability ◽  
History Of ◽  
Phylogenetic Framework ◽  
Phloem Feeding ◽  
Signal Saturation

AbstractWhiteflies (Hemiptera: Sternorrhyncha: Aleyrodidae) are a superfamily of small phloem-feeding insects. Their taxonomy is currently based on the morphology of nymphal stages that display phenotypic plasticity, which produces inconsistencies. To overcome this limitation, we developed a new phylogenetic framework that targets five genes of Candidatus Portiera aleyrodidarum, the primary endosymbiont of whiteflies. Portiera lineages have been co-diverging with whiteflies since their origin and therefore reflect their host evolutionary history. We also studied the origin of stability and instability in Portiera genomes by testing for the presence of two alternative gene rearrangements and the loss of a functional polymerase proofreading subunit (dnaQ), previously associated with genome instability. We present two phylogenetic reconstructions. One using the sequences of all five target genes from 22 whitefly species belonging to 17 genera. The second uses only two genes to include additional published Portiera sequences of 21 whitefly species, increasing our sampling size to 42 species from 25 genera. The developed framework showed low signal saturation, specificity to whitefly samples, and efficiency in solving inter-genera relationships and standing inconsistencies in the current taxonomy of the superfamily. Genome instability was found to be present only in the Aleurolobini tribe containing the Singhiella, Aleurolobus and Bemisia genera. This suggests that Portiera genome instability likely arose in the Aleurolobini tribe’s common ancestor, around 70 Mya. We propose a link between the switch from multi-bacteriocyte to a single-bacteriocyte mode of inheritance in the Aleurolobini tribe and the appearance of genome instability in Portiera.

scholarly journals Comparative transcriptomics of the venoms of continental and insular radiations of West African cones

2020 ◽  
Vol 287 (1929) ◽  
pp. 20200794
Author(s):  
Samuel Abalde ◽  
Manuel J. Tenorio ◽  
Carlos M. L. Afonso ◽  
Rafael Zardoya
Keyword(s):  
Related Species ◽  
Common Ancestor ◽  
West African ◽  
Generic Level ◽  
Closely Related Species ◽  
Functional Convergence ◽  
Venom Glands ◽  
Phylogenetic Framework ◽  
The Common ◽  
Secreted Peptides

The transcriptomes of the venom glands of 13 closely related species of vermivorous cones endemic to West Africa from genera Africonus and Varioconus were sequenced and venom repertoires compared within a phylogenetic framework using one Kalloconus species as outgroup. The total number of conotoxin precursors per species varied between 108 and 221. Individuals of the same species shared about one-fourth of the total conotoxin precursors. The number of common sequences was drastically reduced in the pairwise comparisons between closely related species, and the phylogenetical signal was totally eroded at the inter-generic level (no sequence was identified as shared derived), due to the intrinsic high variability of these secreted peptides. A common set of four conotoxin precursor superfamilies (T, O1, O2 and M) was expanded in all studied cone species, and thus, they are considered the basic venom toolkit for hunting and defense in the West African vermivorous cone snails. Maximum-likelihood ancestral character reconstructions inferred shared conotoxin precursors preferentially at internal nodes close to the tips of the phylogeny (between individuals and between closely related species) as well as in the common ancestor of Varioconus . Besides the common toolkit, the two genera showed significantly distinct catalogues of conotoxin precursors in terms of type of superfamilies present and the abundance of members per superfamily, but had similar relative expression levels indicating functional convergence. Differential expression comparisons between vermivorous and piscivorous cones highlighted the importance of the A and S superfamilies for fish hunting and defense.

scholarly journals Evolutionary History and Activity of RNase H1-Like Proteins in Arabidopsis thaliana

2020 ◽  
Vol 61 (6) ◽  
pp. 1107-1119
Author(s):  
Jan Kuciński ◽  
Sebastian Chamera ◽  
Aleksandra Kmera ◽  
M Jordan Rowley ◽  
Sho Fujii ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Embryonic Development ◽  
Evolutionary History ◽  
Common Ancestor ◽  
Normal Growth ◽  
Plastid Dna ◽  
Growth Conditions ◽  
Replicative Stress ◽  
The Common ◽  
Rna:Dna Hybrids

Abstract RNase H1 is an endonuclease specific toward the RNA strand of RNA:DNA hybrids. Members of this protein family are present in most living organisms and are essential for removing RNA that base pairs with DNA. It prevents detrimental effects of RNA:DNA hybrids and is involved in several biological processes. Arabidopsis thaliana has been previously shown to contain three genes encoding RNase H1 proteins that localize to three distinct cellular compartments. We show that these genes originate from two gene duplication events. One occurred in the common ancestor of dicots and produced nuclear and organellar RNase H1 paralogs. Second duplication occurred in the common ancestor of Brassicaceae and produced mitochondrial- and plastid-localized proteins. These proteins have the canonical RNase H1 activity, which requires at least four ribonucleotides for endonucleolytic digestion. Analysis of mutants in the RNase H1 genes revealed that the nuclear RNH1A and mitochondrial RNH1B are dispensable for development under normal growth conditions. However, the presence of at least one organellar RNase H1 (RNH1B or RNH1C) is required for embryonic development. The plastid-localized RNH1C affects plastid DNA copy number and sensitivity to replicative stress. Our results present the evolutionary history of RNH1 proteins in A. thaliana, demonstrate their canonical RNase H1 activity and indicate their role in early embryonic development.

Bridging Darwin's Origin of Species & Wegener's Origin of Continents and Oceans:

2016 ◽  
Vol 78 (1) ◽  
pp. 24-33 ◽  
Author(s):  
Cristina Sousa
Keyword(s):  
Evolutionary History ◽  
Charles Darwin ◽  
Common Ancestor ◽  
Teaching Strategy ◽  
Origin Of Species ◽  
History Of ◽  
The Common ◽  
Research And Education ◽  
Evolution By Natural Selection ◽  
Biology Research

The common ancestor and evolution by natural selection, concepts introduced by Charles Darwin, constitute the central core of biology research and education. However, students generally struggle to understand these concepts and commonly form misconceptions about them. To help teachers select the most revelant portions of Darwin's work, I suggest some sentences from On the Origin of Species and briefly discuss their implications. I also suggest a teaching strategy that uses history of science and curriculum crosscutting concepts (cause and effect) that constitute the framework to explain the evolutionary history of ratites (flightless birds) as described by Darwin, starting in the Jurassic, with the breakup of Gondwanaland, as first described by Alfred Wegener in The Origin of Continents and Oceans.

scholarly journals Protofeathers were likely to have existed within the common ancestor of dinosaurs

2015 ◽  
Author(s):  
Chan-gyu Yun
Keyword(s):  
Evolutionary History ◽  
Common Ancestor ◽  
Whole Body ◽  
Collagen Fibres ◽  
History Of ◽  
The Common

In this paper, I comment on Barrett et al. (2015) "Evolution of dinosaur epidermal structures". Though the original authors made some very interesting results, the conclusions made by them are likely influenced by inappropriate or incorrect assumptions such as very little preserved skin fragments represent whole body covering or dinosaurian integumentary structures might represent a degraded collagen fibres. Therefore, their result might represent small size of current datas or preservational bias rather than actual evolutionary history of dinosaurian feathers.

scholarly journals The Deep(er) Roots of Eukaryotes and Akaryotes

2020 ◽  
Author(s):  
Ajith Harish ◽  
David A. Morrison
Keyword(s):  
Evolutionary History ◽  
Common Ancestor ◽  
Phylogenetic Signal ◽  
The Other ◽  
Root Node ◽  
Molecular Features ◽  
Universal Common Ancestor ◽  
Evolutionary Relatedness ◽  
The Common ◽  
Phylogenetic Character

AbstractLocating the root-node of the “tree of life” (ToL) is one of the hardest problems in phylogenetics1. The root-node or the universal common ancestor (UCA) divides the descendants into organismal domains2. Two notable variants of the two-domains ToL (2D-ToL) have gained support recently3,4, though, Williams and colleagues (W&C)4 claim that one is better supported than the other. Here, we argue that important aspects of estimating evolutionary relatedness and assessing phylogenetic signal in empirical data were overlooked4. We focus on phylogenetic character reconstructions necessary to describe the UCA or its closest descendants in the absence of reliable fossils. It is well-known that different character-types present different perspectives on evolutionary history that relate to different phylogenetic depths5–7. Which of the 2D-ToL2,4 hypotheses is better supported depends on which kind of molecular features – protein-domains or their component amino-acids – are better for resolving the common ancestors (CA) at the roots of clades. In practice, this involves reconstructing character compositions of the ancestral nodes all the way back to the UCA2,3.

scholarly journals Protofeathers were likely to have existed within the common ancestor of dinosaurs

2015 ◽  
Author(s):  
Chan-gyu Yun
Keyword(s):  
Evolutionary History ◽  
Common Ancestor ◽  
Whole Body ◽  
Collagen Fibres ◽  
History Of ◽  
The Common

In this paper, I comment on Barrett et al. (2015) "Evolution of dinosaur epidermal structures". Though the original authors made some very interesting results, the conclusions made by them are likely influenced by inappropriate or incorrect assumptions such as very little preserved skin fragments represent whole body covering or dinosaurian integumentary structures might represent a degraded collagen fibres. Therefore, their result might represent small size of current datas or preservational bias rather than actual evolutionary history of dinosaurian feathers.

scholarly journals Characterization and Dynamics of Intracellular Gene Transfer in Plastid Genomes of Viola (Violaceae) and Order Malpighiales

2021 ◽  
Vol 12 ◽  
Author(s):  
JiYoung Yang ◽  
Seongjun Park ◽  
Hee-Young Gil ◽  
Jae-Hong Pak ◽  
Seung-Chul Kim
Keyword(s):  
Gene Transfer ◽  
Common Ancestor ◽  
Transit Peptide ◽  
Island Endemic ◽  
Plastid Genomes ◽  
Alternative Mrna Splicing ◽  
Intracellular Gene Transfer ◽  
Phylogenetic Framework ◽  
The Common ◽  
Functional Replacement

Functional gene transfer from organelles to the nucleus, known as intracellular gene transfer (IGT), is an ongoing process in flowering plants. The complete plastid genomes (plastomes) of two Ulleung island endemic violets, Viola ulleungdoensis and V. woosanensis, were characterized, revealing a lack of the plastid-encoded infA, rpl32, and rps16 genes. In addition, functional replacement of the three plastid-encoded genes in the nucleus was confirmed within the genus Viola and the order Malpighiales. Three strategies for the acquisition of a novel transit peptide for successful IGT were identified in the genus Viola. Nuclear INFA acquired a novel transit peptide with very low identity between these proteins, whereas the nuclear RPL32 gene acquired an existing transit peptide via fusion with the nuclear-encoded plastid-targeted SOD gene (Cu-Zn superoxide dismutase superfamily) as one exon, and translated both proteins in the cytosol using alternative mRNA splicing. Nuclear RPS16 contains an internal transit peptide without an N-terminal extension. Gene loss or pseudogenization of the plastid-borne rpl32 and rps16 loci was inferred to occur in the common ancestor of the genus Viola based on an infrageneric phylogenetic framework in Korea. Although infA was lost in the common ancestor of the order Malpighiales, the rpl32 and rps16 genes were lost multiple times independently within the order. Our current study sheds additional light on plastid genome composition and IGT mechanisms in the violet genus and in the order Malpighiales.

First North African record of a melanistic common genet (Genetta genetta Linnaeus, 1758)

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mourad Ahmim ◽  
Hafid Aroudj ◽  
Farouk Aroudj ◽  
Saaid Saidi ◽  
Samir Aroudj
Keyword(s):  
North Africa ◽  
Evolutionary History ◽  
North African ◽  
Mammal Species ◽  
Genetta Genetta ◽  
History Of ◽  
The Common ◽  
True Occurrence

Abstract The common genet (Genetta genetta Linnaeus, 1758) is a rare and protected mammal species in Algeria. We report the first melanistic individual of this species ever recorded in North Africa. Such animals have only been recorded in Spain and Portugal so far. It is unclear why melanistic common genets seem to be so rare in its African range. More research is needed to determine the true occurrence of melanistic individuals, and what the evolutionary history of melanism is in common genets.

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