scholarly journals Patterns of evolution of genes disrupted in expression in Drosophila species hybrids

2005 ◽  
Vol 85 (2) ◽  
pp. 119-125 ◽  
Author(s):  
MOHAMED A. F. NOOR
Keyword(s):  
Amino Acid ◽  
Parental Species ◽  
Species Group ◽  
Pure Species ◽  
X Chromosomes ◽  
Regulatory Pathways ◽  
Regulatory Architecture ◽  
Species Groups ◽  
Male Specific ◽  
Species Hybrids

Divergence between species in regulatory pathways may contribute to hybrid incompatibilities such as sterility. Consistent with this idea, genes involved in male fertility often evolve faster than most other genes both in amino acid sequence and in expression. Previously, we identified a panel of male-specific genes underexpressed in sterile male hybrids of Drosophila simulans and D. mauritiana relative to pure species, and we showed that this underexpression is associated with infertility. In a preliminary effort to assess the generalities in the patterns of evolution of these genes, I examined patterns of mRNA expression in three of these genes in sterile F1 hybrid males of D. pseudoobscura and D. persimilis. F1 hybrid males bearing D. persimilis X chromosomes underexpressed all these genes relative to the parental species, while hybrids bearing D. pseudoobscura X chromosomes underexpressed two of these three genes. Interestingly, the third gene, CG5762, has undergone extensive amino acid evolution within the D. pseudoobscura species group, possibly driven by positive natural selection. We conclude that some of the same genes exhibit disruptions in expression within each of the two species groups, which could suggest commonalities in the regulatory architecture of sterility in these groups. Alternative explanations are also considered.

Review of species of the genus Cercyon of Russia and adjacent regions. VI. Subgenus Cercyon, the C.shinanensis group (Coleoptera: Hydrophilidae)

2019 ◽  
Vol 28 (2) ◽  
pp. 258-266 ◽  
Author(s):  
S.K. Ryndevich ◽  
H. Hoshina ◽  
A.A. Prokin
Keyword(s):  
Russian Far East ◽  
Far East ◽  
Species Group ◽  
Palaearctic Species ◽  
Diagnostic Features ◽  
Kunashir Island ◽  
Species Groups ◽  
The Russian Far East

The Cercyon shinanensis species group with two included species is erected within the nominotypical subgenus of Cercyon Leach, 1817. This group is compared with other Palaearctic species groups of Cercyon s. str. The little-known C. shinanensis Nakane, 1965 from Japan (Honshu) is redescribed and its diagnostic features are given. Cercyon sundukovi sp. nov. is described from the Russian Far East (Kunashir Island).

scholarly journals Genetic Screens for Factors Involved in the Notum Bristle Loss of Interspecific Hybrids Between Drosophila melanogaster and D. simulans

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 269-282
Author(s):  
Toshiyuki Takano-Shimizu
Keyword(s):  
Drosophila Melanogaster ◽  
Interspecific Cross ◽  
Species Variation ◽  
Genetic Screens ◽  
Pure Species ◽  
Epistatic Interactions ◽  
X Chromosomes ◽  
Powerful Means ◽  
Different Populations ◽  
Deficiency Screening

Abstract Interspecific cross is a powerful means to uncover hidden within- and between-species variation in populations. One example is a bristle loss phenotype of hybrids between Drosophila melanogaster and D. simulans, although both the pure species have exactly the same pattern of bristle formation on the notum. There exists a large amount of genetic variability in the simulans populations with respect to the number of missing bristles in hybrids, and the variation is largely attributable to simulans X chromosomes. Using nine molecular markers, I screened the simulans X chromosome for genetic factors that were responsible for the differences between a pair of simulans lines with high (H) and low (L) missing bristle numbers. Together with duplication-rescue experiments, a single major quantitative locus was mapped to a 13F–14F region. Importantly, this region accounted for most of the differences between H and L lines in three other independent pairs, suggesting segregation of H and L alleles at the single locus in different populations. Moreover, a deficiency screening uncovered several regions with factors that potentially cause the hybrid bristle loss due to epistatic interactions with the other factors.

Discovery of New Genera Challenges the Subtribal Classification of Tok-Tok Beetles (Coleoptera: Tenebrionidae: Sepidiini)

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Olivia M Gearner ◽  
Marcin J Kamiński ◽  
Kojun Kanda ◽  
Kali Swichtenberg ◽  
Aaron D Smith
Keyword(s):  
Dna Sequences ◽  
Species Group ◽  
Phylogenetic Placement ◽  
Darkling Beetles ◽  
Species Groups ◽  
Taxonomic Groups ◽  
Inference Methods ◽  
A New Species ◽  
Coleoptera Tenebrionidae

Abstract Sepidiini is a speciose tribe of desert-inhabiting darkling beetles, which contains a number of poorly defined taxonomic groups and is in need of revision at all taxonomic levels. In this study, two previously unrecognized lineages were discovered, based on morphological traits, among the extremely speciose genera Psammodes Kirby, 1819 (164 species and subspecies) and Ocnodes Fåhraeus, 1870 (144 species and subspecies), namely the Psammodes spinosus species-group and Ocnodes humeralis species-group. In order to test their phylogenetic placement, a phylogeny of the tribe was reconstructed based on analyses of DNA sequences from six nonoverlapping genetic loci (CAD, wg, COI JP, COI BC, COII, and 28S) using Bayesian and maximum likelihood inference methods. The aforementioned, morphologically defined, species-groups were recovered as distinct and well-supported lineages within Molurina + Phanerotomeina and are interpreted as independent genera, respectively, Tibiocnodes Gearner & Kamiński gen. nov. and Tuberocnodes Gearner & Kamiński gen. nov. A new species, Tuberocnodes synhimboides Gearner & Kamiński sp. nov., is also described. Furthermore, as the recovered phylogenetic placement of Tibiocnodes and Tuberocnodes undermines the monophyly of Molurina and Phanerotomeina, an analysis of the available diagnostic characters for those subtribes is also performed. As a consequence, Phanerotomeina is considered as a synonym of the newly redefined Molurina sens. nov. Finally, spectrograms of vibrations produced by substrate tapping of two Molurina species, Toktokkus vialis (Burchell, 1822) and T. synhimboides, are presented.

scholarly journals Absence of X-chromosome dosage compensation in the primordial germ cells of Drosophila embryos

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryoma Ota ◽  
Makoto Hayashi ◽  
Shumpei Morita ◽  
Hiroki Miura ◽  
Satoru Kobayashi
Keyword(s):  
X Chromosome ◽  
Germ Cells ◽  
Dosage Compensation ◽  
Sex Chromosome ◽  
Primordial Germ Cells ◽  
Histone H4 ◽  
X Chromosomes ◽  
Essential Components ◽  
Msl Complex ◽  
Male Specific

AbstractDosage compensation is a mechanism that equalizes sex chromosome gene expression between the sexes. In Drosophila, individuals with two X chromosomes (XX) become female, whereas males have one X chromosome (XY). In males, dosage compensation of the X chromosome in the soma is achieved by five proteins and two non-coding RNAs, which assemble into the male-specific lethal (MSL) complex to upregulate X-linked genes twofold. By contrast, it remains unclear whether dosage compensation occurs in the germline. To address this issue, we performed transcriptome analysis of male and female primordial germ cells (PGCs). We found that the expression levels of X-linked genes were approximately twofold higher in female PGCs than in male PGCs. Acetylation of lysine residue 16 on histone H4 (H4K16ac), which is catalyzed by the MSL complex, was undetectable in these cells. In male PGCs, hyperactivation of X-linked genes and H4K16ac were induced by overexpression of the essential components of the MSL complex, which were expressed at very low levels in PGCs. Together, these findings indicate that failure of MSL complex formation results in the absence of X-chromosome dosage compensation in male PGCs.

Beyond Wallace: a new lineage of Chrysorthenches (Lepidoptera: Yponomeutoidea: Glyphipterigidae) reveals a journey tracking its host-plants, Podocarpus (Pinopsida: Podocarpaceae)

2020 ◽  
Vol 190 (2) ◽  
pp. 709-736
Author(s):  
Jae-Cheon Sohn ◽  
Shigeki Kobayashi ◽  
Yutaka Yoshiyasu
Keyword(s):  
Maximum Likelihood ◽  
East Asia ◽  
Host Plants ◽  
Morphological Characters ◽  
Species Group ◽  
Geological History ◽  
Dna Barcodes ◽  
History Of ◽  
Species Groups ◽  
Maximum Likelihood Phylogeny

Abstract A northward trans-Wallacean radiation is demonstrated for Chrysorthenches, a member of the Orthenches group. Here we review Chrysorthenches and allied genera resulting in a generic transfer of Diathryptica callibrya to Chrysorthenches and two new congeners: C. muraseaeSohn & Kobayashisp. nov. from Japan and C. smaragdinaSohnsp. nov. from Thailand. We review morphological characters of Chrysorthenches and allied genera, and find polyphyly of Diathryptica and the association of the Orthenches-group with Glyphipterigidae. These findings were supported in a maximum likelihood phylogeny of DNA barcodes from ten yponomeutoids. We analysed 30 morphological characters for 12 species of Chrysorthenches, plus one outgroup, via a cladistic approach. The resulting cladogram redefined two pre-existing Chrysorthenches species-groups and identified one novel lineage: the C. callibrya species-group. We review the host associations between Chrysorthenches and Podocarpaceae, based on mapping the working phylogenies. Our review suggests that ancestral Chrysorthenches colonized Podocarpus and later shifted to other podocarp genera. Biogeographical patterns of Chrysorthenches show that they evolved long after the Podocarpaceae radiation. Disjunctive trans-Wallacean distribution of the C. callibrya species-group is possibly related to the tracking of their host-plants and the complicated geological history of the island-arc system connecting Australia and East Asia.

Revision of the Metallactus kollari species-group with a new diagnosis of the genus (Coleoptera: Chrysomelidae: Cryptocephalinae)

Zootaxa ◽  
2018 ◽  
Vol 4413 (1) ◽  
pp. 57
Author(s):  
DAVIDE SASSI
Keyword(s):  
Type Species ◽  
Species Group ◽  
Identification Key ◽  
Original Diagnosis ◽  
Taxonomic Treatment ◽  
Species Groups ◽  
New Diagnosis ◽  
Good Resource

The genus Metallactus has been controversial since its introduction due to the ambiguous nature of the original diagnosis. This has caused some confusion in the taxonomy of Neotropical Pachybrachina. In this work the morphology of endophallus, which is useful for the characterization of species groups in several groups of Coleoptera, including Cryptocephalinae, has been analyzed. This has proven to be a good resource also in the taxonomic treatment of the species belonging to the genus Metallactus. After a careful survey on most of the species described so far, the endophallus shape in Metallactus turned out to be remarkably distinctive and very promising in the delimitation of species groups. The present work includes: a) a new diagnosis of the genus Metallactus on the basis of the aedeagal anatomy; b) the designation of the type species of the nominal genus; c) the revision of a first species-group of the genus, including the type species, hereinafter called Metallactus kollari species-group. Before this revision, catalogues had been reporting 13 species attributable to this group, in the present work three species have been synonymized and seven have been described as new to science. Therefore, the group includes 17 species. The species described as new are: Metallactus rileyi n. sp., M. bellatrix n. sp., M. longicornis n. sp.; M. londonpridei n. sp., M. regalini n. sp., M. bezoar n. sp., M. guarani n. sp. The new synonymies are as follows: Metallactus albipes Suffrian, 1866 (= M. nigrofasciatus Suffrian, 1866 n. syn.), M. albifrons Suffrian, 1866 (= M. flavofrontalis Jacoby, 1907 n. syn.), M. dodecastictus Suffrian, 1866 (= Griburius nigritarsis Jacoby, 1907 n. syn.). The lectotypes of all previously described species have been designated. The new synonymies, the name-bearing type fixations and designations and the nomenclatural acts have been critically discussed. An identification key for the species-group is also provided. 

scholarly journals Individuals from different-looking animal species may group together to confuse shared predators: simulations with artificial neural networks

2006 ◽  
Vol 274 (1611) ◽  
pp. 827-832 ◽  
Author(s):  
Colin R Tosh ◽  
Andrew L Jackson ◽  
Graeme D Ruxton
Keyword(s):  
Animal Species ◽  
Empirical Work ◽  
Species Group ◽  
Mixed Species ◽  
Retinotopic Maps ◽  
Species Groups ◽  
Artificial Neural ◽  
Mixed Species Groups ◽  
Species Grouping ◽  
Prey Items

Individuals of many quite distantly related animal species find each other attractive and stay together for long periods in groups. We present a mechanism for mixed-species grouping in which individuals from different-looking prey species come together because the appearance of the mixed-species group is visually confusing to shared predators. Using an artificial neural network model of retinotopic mapping in predators, we train networks on random projections of single- and mixed-species prey groups and then test the ability of networks to reconstruct individual prey items from mixed-species groups in a retinotopic map. Over the majority of parameter space, cryptic prey items benefit from association with conspicuous prey because this particular visual combination worsens predator targeting of cryptic individuals. However, this benefit is not mutual as conspicuous prey tends to be targeted most poorly when in same-species groups. Many real mixed-species groups show the asymmetry in willingness to initiate and maintain the relationship predicted by our study. The agreement of model predictions with published empirical work, the efficacy of our modelling approach in previous studies, and the taxonomic ubiquity of retinotopic maps indicate that we may have uncovered an important, generic selective agent in the evolution of mixed-species grouping.

Three new Anaulacomera species (Orthoptera: Tettigoniidae: Phaneropterinae) from the Iguaçu National Park and nearby areas, southern Brazil

Zootaxa ◽  
2021 ◽  
Vol 5061 (2) ◽  
pp. 340-352
Author(s):  
MARCOS FIANCO ◽  
OSCAR J. CADENA-CASTAÑEDA ◽  
NEUCIR SZINWELSKI ◽  
LUIZ R. R. FARIA
Keyword(s):  
New Species ◽  
Atlantic Forest ◽  
National Park ◽  
Species Group ◽  
Southern Brazil ◽  
Distribution Maps ◽  
Incertae Sedis ◽  
Present Distribution ◽  
Species Groups ◽  
Three New Species

Three new species of Anaulacomera are described, Anaulacomera (Anaulacomera) mariellae sp. n. and Anaulacomera (Anallomes) arlindoi sp. n., belonging respectively to the Inermis and Lanceolata species group, and Anaulacomera angelinae sp. n., placed as incertae sedis. The individuals were collected at the Iguaçu National Park and adjacent small fragments of Atlantic Forest, in southwestern Paraná state, Brazil. The description was based on external morphology of males. We also present distribution maps for the species of the Inermis and the Lanceolata species groups.  

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