scholarly journals A genetic switch for male UV iridescence in an incipient species pair of sulphur butterflies

2022 ◽  
Vol 119 (3) ◽  
pp. e2109255118
Author(s):  
Vincent Ficarrotta ◽  
Joseph J. Hanly ◽  
Ling S. Loh ◽  
Caroline M. Francescutti ◽  
Anna Ren ◽  
...  
Keyword(s):  
Linkage Mapping ◽  
Secondary Contact ◽  
Eastern United States ◽  
Genetic Switch ◽  
Incipient Species ◽  
Intermediate Phases ◽  
Courtship Signal ◽  
Species Formation ◽  
Genomic Landscape

Mating cues evolve rapidly and can contribute to species formation and maintenance. However, little is known about how sexual signals diverge and how this variation integrates with other barrier loci to shape the genomic landscape of reproductive isolation. Here, we elucidate the genetic basis of ultraviolet (UV) iridescence, a courtship signal that differentiates the males of Colias eurytheme butterflies from a sister species, allowing females to avoid costly heterospecific matings. Anthropogenic range expansion of the two incipient species established a large zone of secondary contact across the eastern United States with strong signatures of genomic admixtures spanning all autosomes. In contrast, Z chromosomes are highly differentiated between the two species, supporting a disproportionate role of sex chromosomes in speciation known as the large-X (or large-Z) effect. Within this chromosome-wide reproductive barrier, linkage mapping indicates that cis-regulatory variation of bric a brac (bab) underlies the male UV-iridescence polymorphism between the two species. Bab is expressed in all non-UV scales, and butterflies of either species or sex acquire widespread ectopic iridescence following its CRISPR knockout, demonstrating that Bab functions as a suppressor of UV-scale differentiation that potentiates mating cue divergence. These results highlight how a genetic switch can regulate a premating signal and integrate with other reproductive barriers during intermediate phases of speciation.

scholarly journals A genetic switch for male UV-iridescence in an incipient species pair of sulphur butterflies

2021 ◽  
Author(s):  
Vincent Ficarrotta ◽  
Joseph J Hanly ◽  
Ling S Loh ◽  
Caroline M Francescutti ◽  
Anna Ren ◽  
...  
Keyword(s):  
Genetic Basis ◽  
Secondary Contact ◽  
Sexual Signals ◽  
Genetic Switch ◽  
Knock Out ◽  
Incipient Species ◽  
Courtship Signal ◽  
Species Formation ◽  
Genomic Landscape

Mating cues evolve rapidly and can contribute to species formation and maintenance. However, little is known about how sexual signals diverge and how this variation integrates with other barrier loci to shape the genomic landscape of reproductive isolation. Here, we elucidate the genetic basis of UV iridescence, a courtship signal that differentiates the males of Colias eurytheme butterflies from a sister species, allowing females to avoid costly heterospecific matings. Anthropogenic range expansion of the two incipient species established a large zone of secondary contact across the eastern US with strong signatures of genomic admixtures spanning all autosomes. In contrast, Z chromosomes are highly differentiated between the two species, supporting a disproportionate role of sex chromosomes in speciation known as the large-X effect. Within this chromosome-wide reproductive barrier, cis-regulatory variation of bric a brac (bab) drives the male UV-iridescence polymorphism between the two species. Bab is expressed in all non-UV scales, and butterflies of either species or sex acquire widespread ectopic iridescence following its CRISPR knock-out, demonstrating that Bab functions as a suppressor of UV-scale differentiation that potentiates mating cue divergence. These results provide new insights into the diversification of sexual signals and the species concept.

scholarly journals How Facilitation May Interfere with Ecological Speciation

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
P. Liancourt ◽  
P. Choler ◽  
N. Gross ◽  
X. Thibert-Plante ◽  
K. Tielbörger
Keyword(s):  
Ecological Speciation ◽  
Theoretical Research ◽  
Secondary Contact ◽  
Positive Interactions ◽  
Evolutionary Diversification ◽  
Incipient Species ◽  
Modelling Framework ◽  
Vast Literature ◽  
Marginal Habitats

Compared to the vast literature linking competitive interactions and speciation, attempts to understand the role of facilitation for evolutionary diversification remain scarce. Yet, community ecologists now recognize the importance of positive interactions within plant communities. Here, we examine how facilitation may interfere with the mechanisms of ecological speciation. We argue that facilitation is likely to (1) maintain gene flow among incipient species by enabling cooccurrence of adapted and maladapted forms in marginal habitats and (2) increase fitness of introgressed forms and limit reinforcement in secondary contact zones. Alternatively, we present how facilitation may favour colonization of marginal habitats and thus enhance local adaptation and ecological speciation. Therefore, facilitation may impede or pave the way for ecological speciation. Using a simple spatially and genetically explicit modelling framework, we illustrate and propose some first testable ideas about how, when, and where facilitation may act as a cohesive force for ecological speciation. These hypotheses and the modelling framework proposed should stimulate further empirical and theoretical research examining the role of both competitive and positive interactions in the formation of incipient species.

The use of scanning electron microscopy in interpreting chenopodium remains from three archaeological sites in northwestern Iowa

1992 ◽  
Vol 50 (2) ◽  
pp. 1112-1113
Author(s):  
Douglas William Jones
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Archaeological Sites ◽  
Late Prehistoric ◽  
Eastern United States ◽  
Chenopodium Berlandieri ◽  
Seed Identification ◽  
Level 2 ◽  
Scanning Electron

Within the past 20 years, archaeobotanical research in the Eastern United States has documented an early agricultural complex before the dominance of the Mesoamerican domesticates (corn, beans, and squash) in late prehistoric and historic agricultural systems. This early agricultural complex consisted of domesticated plants such as Iva annua var.macrocarpa (Sumpweed or Marshelder), Hellanthus annuus (Sunflower) and Chenopodium berlandieri, (Goosefoot or Lasbsquarters), and heavily utilized plants such as Polygonum erectum (Erect Knotweed), Phalaris caroliniana (May grass), and Hordeum pusillum (Little Barley).Recent research involving the use of Scanning Electron Microscopy (SEM) specifically on Chenopodium has established diagnostic traits of wild and domesticated species seeds. This is important because carbonized or uncarbonized seeds are the most commonly recovered Chenopodium material from archaeological sites. The diagnostic seed traits assist archaeobotanists in identification of Chenopodium remains and provide a basis for evaluation of Chenopodium utilization in a culture's subsistence patterns. With the aid of SEM, an analysis of Chenopodium remains from three Late Prehistoric sites in Northwest Iowa (Blood Run [Oneota culture], Brewster [Mill Creek culture], and Chan-Ya-Ta [Mill Creek culture]) has been conducted to: 1) attempt seed identification to a species level, 2) evaluate the traits of the seeds for classification as either wild or domesticated, and 3) evaluate the role of Chenopodium utilization in both the Oneota and Mill Creek cultures.

scholarly journals Analysis of the genomic landscape of yolk sac tumors reveals mechanisms of evolution and chemoresistance

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xuan Zong ◽  
Ying Zhang ◽  
Xinxin Peng ◽  
Dongyan Cao ◽  
Mei Yu ◽  
...  
Keyword(s):  
Copy Number Alteration ◽  
Germ Cell Tumors ◽  
Gonadal Development ◽  
Yolk Sac ◽  
Mutational Signatures ◽  
Whole Exome ◽  
Genomic Landscape ◽  
Yolk Sac Tumors ◽  
Molecular Aberrations

AbstractYolk sac tumors (YSTs) are a major histological subtype of malignant ovarian germ cell tumors with a relatively poor prognosis. The molecular basis of this disease has not been thoroughly characterized at the genomic level. Here we perform whole-exome and RNA sequencing on 41 clinical tumor samples from 30 YST patients, with distinct responses to cisplatin-based chemotherapy. We show that microsatellite instability status and mutational signatures are informative of chemoresistance. We identify somatic driver candidates, including significantly mutated genes KRAS and KIT and copy-number alteration drivers, including deleted ARID1A and PARK2, and amplified ZNF217, CDKN1B, and KRAS. YSTs have very infrequent TP53 mutations, whereas the tumors from patients with abnormal gonadal development contain both KRAS and TP53 mutations. We further reveal a role of OVOL2 overexpression in YST resistance to cisplatin. This study lays a critical foundation for understanding key molecular aberrations in YSTs and developing related therapeutic strategies.

A Simple Dissolved Metals Mixing Route to Prepare Nanostructured Mg0.8Zn0.2TiO3 Solid Solution

2015 ◽  
Vol 1112 ◽  
pp. 47-52 ◽  
Author(s):  
Frida Ulfah Ermawati ◽  
Suasmoro Suasmoro ◽  
Suminar Pratapa
Keyword(s):  
Solid Solution ◽  
Particle Size ◽  
Rietveld Analysis ◽  
Dissolved Metals ◽  
Intermediate Phases ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Xrd Patterns ◽  
Zn Ions

A study of liquid mixing route to synthesize high purity Mg0.8Zn0.2TiO3 nanopowder, a candidate dielectric ceramics, has been successfully performed. Formation of the phases on the dried powder was studied using TG/DTA, XRD and FT-IR data. Rietveld analysis on the collected XRD patterns confirmed the formation of solid solution in the system. Such solid solution can be obtained from the powder calcined at 500 °C, but calcination at 550 °C gave rise to the most optimum molar purity up to 98.5% without intermediate phases. The role of Zn ions on the formation of solid solution was also discussed. Homogeneity of particle size distribution and nano-crystallinity of the system was verified from the particle size analyzer data, TEM image and the Rietveld analysis output.

Exclusion of the Role of Secondary Contact in an Allele Frequency Cline in the Mussel Mutilus edulis

Evolution ◽  
1985 ◽  
Vol 39 (2) ◽  
pp. 432 ◽  
Author(s):  
Thomas J. Hilbish ◽  
Richard K. Koehn
Keyword(s):  
Allele Frequency ◽  
Secondary Contact

Extensive hybridization between two Andean warbler species with shallow divergence in mtDNA

The Auk ◽  
2021 ◽  
Vol 138 (1) ◽  
Author(s):  
Laura N Céspedes-Arias ◽  
Andrés M Cuervo ◽  
Elisa Bonaccorso ◽  
Marialejandra Castro-Farias ◽  
Alejandro Mendoza-Santacruz ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Contact Zone ◽  
Hybrid Zone ◽  
Secondary Contact ◽  
Tropical Andes ◽  
Phenotypic Data ◽  
Geographic Ranges ◽  
Intermediate Phenotypes ◽  
Ecological Barriers

Abstract Studying processes acting on differentiated populations upon secondary contact, such as hybridization, is important to comprehensively understand how species are formed and maintained over time. However, avian speciation studies in the tropical Andes have largely focused on the role of topographic and ecological barriers promoting divergence in allopatry, seldom examining hybridization and introgression. We describe a hybrid zone involving 2 closely related Andean warblers (Parulidae), the Golden-fronted Redstart (Myioborus ornatus), and the Spectacled Redstart (Myioborus melanocephalus). Geographic ranges of these species abut near the Colombia-Ecuador border and many specimens from the region exhibit intermediate phenotypes, but a formal description of phenotypic variation in the contact zone was heretofore lacking. We collected specimens across a transect encompassing the area where ranges abut and areas where only “pure” parental phenotypes of M. ornatus chrysops and M. melanocephalus ruficoronatus occur. We described variation in plumage traits including patterns of head and ventral coloration and tail markings based on 321 specimens. To describe genetic variation in the contact zone and over a broader phylogeographic context, we used sequences of the mitochondrial ND2 gene for 219 individuals across the transect and the entire range of both species, including all subspecies, from Venezuela to Bolivia. We documented a hybrid zone ~200 km wide based on head coloration, where intermediate plumage phenotypes are most common and “pure” forms do not overlap geographically, consistent with extensive hybridization. Across the range of the M. ornatus–M. melanocephalus complex, mitochondrial genetic structure was shallow, with genetic breaks only coinciding clearly with one topographic feature. Such a low genetic structure is striking given the high diversity in plumage phenotypes and the current taxonomy of the group. Our phenotypic data suggest that barriers to hybridization are not strong, and allow us to postulate hypotheses to be tested using forthcoming genomic data.

Cryptic Diversity and Sexual Selection

2020 ◽  
pp. 447-471
Author(s):  
Matthias Galipaud ◽  
Loïc Bollache ◽  
Clément Lagrue
Keyword(s):  
Sexual Selection ◽  
Morphological Traits ◽  
Character Displacement ◽  
Secondary Contact ◽  
Cryptic Diversity ◽  
Reproductive Character Displacement ◽  
Behavioral Traits ◽  
Genetic Techniques ◽  
Existing Data

Recent advances in molecular and genetic techniques have revealed tremendous hidden genetic diversity in plants and animals. Crustaceans are no exception and, in fact, present one of the highest levels of cryptic diversity among the metazoans. Beyond the importance of such discovery and its multiple implications for taxonomy and ecology, it is now timely to investigate the potential causes of cryptic diversity. This chapter reviews the theoretical and experimental literature, seeking evidences for a relationship between sexual selection and cryptic diversity in crustaceans. It proposes three scenarios for the role of sexual selection on the origin and maintenance of pre-mating isolation and genetic divergence among crustacean populations, and suggests ways to discriminate among them experimentally or using existing data. Assuming that taxonomic identification is largely based on differences in sexually selected morphological traits, it also reviews evidence for a cryptic action of sexual selection on crustacean phenotypes. Specifically, if sexual selection acts primarily on chemical, visual, or behavioral traits, it is likely that allopatric crustacean populations remain morphologically similar even when they are reproductively isolated. This review shows that the strength of sexual selection likely differs among allopatric populations but does not seem to consistently induce pre-mating isolation (e.g. as in copepods and amphipods). Research is now needed to try to identify general patterns and determine the role of sexual selection on pre-mating isolation after secondary contact between populations, through reinforcement and reproductive character displacement.

Zinc diffusion induced precipitation of σ-phase in austenitic stainless steel

2019 ◽  
Vol 116 (6) ◽  
pp. 618
Author(s):  
Nega Setargew ◽  
Daniel J. Parker
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Intermetallic Phase ◽  
Austenitic Stainless Steels ◽  
Austenite Matrix ◽  
Σ Phase ◽  
Intermediate Phases ◽  
Zinc Diffusion

Zinc diffusion-induced degradation of AISI 316LN austenitic stainless steel pot equipment used in 55%Al-Zn and Zn-Al-Mg coating metal baths is described. SEM/EDS analyses results showed that the diffused zinc reacts with nickel from the austenite matrix and results in the formation of Ni-Zn intermetallic compounds. The Ni-Zn intermetallic phase and the nickel depleted zones form a periodic and alternating layered structure and a mechanism for its formation is proposed. The role of cavities and interconnected porosity in zinc vapour diffusion-induced degradation and formation of Ni-Zn intermediate phases is also discussed. The formation of Ni-Zn intermediate phases and the depletion of nickel in the austenite matrix results in the precipitation of σ-phase and α-ferrite in the nickel depleted regions of the matrix. This reaction will lead to increased susceptibility to intergranular cracking and accelerated corrosion of immersed pot equipment in the coating bath. Zinc diffusion induced precipitation of σ-phase in austenitic stainless steels that we are reporting in this work is a new insight with important implications for the performance of austenitic stainless steels in zinc containing metal coating baths and other process industries. This new insight will further lead to improved understanding of the role of substitutional diffusion and the redistribution of alloying elements in the precipitation of σ-phase in austenitic stainless steels.

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