scholarly journals Landscape resistance constrains hybridization across contact zones in a reproductively and morphologically polymorphic salamander

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guillermo Velo-Antón ◽  
André Lourenço ◽  
Pedro Galán ◽  
Alfredo Nicieza ◽  
Pedro Tarroso
Keyword(s):  
Contact Zone ◽  
Environmental Heterogeneity ◽  
Evolutionary Dynamics ◽  
Morphological Differentiation ◽  
Phenotypic Traits ◽  
Hybrid Zones ◽  
Landscape Resistance ◽  
Phenotypic Differentiation ◽  
Contact Zones

AbstractExplicitly accounting for phenotypic differentiation together with environmental heterogeneity is crucial to understand the evolutionary dynamics in hybrid zones. Species showing intra-specific variation in phenotypic traits that meet across environmentally heterogeneous regions constitute excellent natural settings to study the role of phenotypic differentiation and environmental factors in shaping the spatial extent and patterns of admixture in hybrid zones. We studied three environmentally distinct contact zones where morphologically and reproductively divergent subspecies of Salamandra salamandra co-occur: the pueriparous S. s. bernardezi that is mostly parapatric to its three larviparous subspecies neighbours. We used a landscape genetics framework to: (i) characterise the spatial location and extent of each contact zone; (ii) assess patterns of introgression and hybridization between subspecies pairs; and (iii) examine the role of environmental heterogeneity in the evolutionary dynamics of hybrid zones. We found high levels of introgression between parity modes, and between distinct phenotypes, thus demonstrating the evolution to pueriparity alone or morphological differentiation do not lead to reproductive isolation between these highly divergent S. salamandra morphotypes. However, we detected substantial variation in patterns of hybridization across contact zones, being lower in the contact zone located on a topographically complex area. We highlight the importance of accounting for spatial environmental heterogeneity when studying evolutionary dynamics of hybrid zones.

scholarly journals Spatial and Temporal Dynamics of Contact Zones Between Chromosomal Races of House Mice, Mus musculus domesticus, on Madeira Island

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 748 ◽  
Author(s):  
Joaquim T. Tapisso ◽  
Sofia I. Gabriel ◽  
Ana Mota Cerveira ◽  
Janice Britton-Davidian ◽  
Guila Ganem ◽  
...  
Keyword(s):  
Contact Zone ◽  
Temporal Dynamics ◽  
Significant Shift ◽  
Mus Musculus Domesticus ◽  
Landscape Resistance ◽  
Sampling Area ◽  
Contact Zones ◽  
Madeira Island ◽  
The North ◽  
Chromosomal Races

Analysis of contact zones between parapatric chromosomal races can help our understanding of chromosomal divergence and its influence on the speciation process. Monitoring the position and any movement of contact zones can allow particular insights. This study investigates the present (2012–2014) and past (1998–2002) distribution of two parapatric house mouse chromosomal races—PEDC (Estreito da Calheta) and PADC (Achadas da Cruz)—on Madeira Island, aiming to identify changes in the location and width of their contact. We also extended the 1998–2002 sampling area into the range of another chromosomal race—PLDB (Lugar de Baixo). Clinal analysis indicates no major geographic alterations in the distribution and chromosomal characteristics of the PEDC and PADC races but exhibited a significant shift in position of the Rb (7.15) fusion, resulting in the narrowing of the contact zone over a 10+ year period. We discuss how this long-lasting contact zone highlights the role of landscape on mouse movements, in turn influencing the chromosomal characteristics of populations. The expansion of the sampling area revealed new chromosomal features in the north and a new contact zone in the southern range involving the PEDC and PLDB races. We discuss how different interacting mechanisms (landscape resistance, behaviour, chromosomal incompatibilities, meiotic drive) may help to explain the pattern of chromosomal variation at these contacts between chromosomal races.

scholarly journals Environmental Heterogeneity and Phenotypic Divergence: Can Heritable Epigenetic Variation Aid Speciation?

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Ruth Flatscher ◽  
Božo Frajman ◽  
Peter Schönswetter ◽  
Ovidiu Paun
Keyword(s):  
Biological Sciences ◽  
Environmental Heterogeneity ◽  
Phenotypic Diversity ◽  
Adaptive Strategies ◽  
Epigenetic Variation ◽  
Adaptive Responses ◽  
Adaptive Traits ◽  
Phenotypic Differentiation ◽  
Genome Wide

The dualism of genetic predisposition and environmental influences, their interactions, and respective roles in shaping the phenotype have been a hot topic in biological sciences for more than two centuries. Heritable epigenetic variation mediates between relatively slowly accumulating mutations in the DNA sequence and ephemeral adaptive responses to stress, thereby providing mechanisms for achieving stable, but potentially rapidly evolving phenotypic diversity as a response to environmental stimuli. This suggests that heritable epigenetic signals can play an important role in evolutionary processes, but so far this hypothesis has not been rigorously tested. A promising new area of research focuses on the interaction between the different molecular levels that produce phenotypic variation in wild, closely-related taxa that lack genome-wide genetic differentiation. By pinpointing specific adaptive traits and investigating the mechanisms responsible for phenotypic differentiation, such study systems could allow profound insights into the role of epigenetics in the evolution and stabilization of phenotypic discontinuities, and could add to our understanding of adaptive strategies to diverse environmental conditions and their dynamics.

scholarly journals The role of multiple reproductive barriers: strong post-pollination interactions govern cytotype isolation in a tetraploid–octoploid contact zone

2020 ◽  
Vol 126 (6) ◽  
pp. 991-1003 ◽  
Author(s):  
Mariana Castro ◽  
João Loureiro ◽  
Brian C Husband ◽  
Sílvia Castro
Keyword(s):  
Reproductive Isolation ◽  
Contact Zone ◽  
Assortative Mating ◽  
Reproductive Barriers ◽  
Pollinator Behaviour ◽  
Contact Zones ◽  
Foraging Preferences ◽  
Flowering Asynchrony ◽  
Gametic Selection

Abstract Background and Aims Polyploidy is an important contributor to sympatric speciation and assortative mating is a key mechanism driving cytotype interactions in contact zones. While strong reproductive barriers can mediate the coexistence of different cytotypes in sympatry, positive frequency-dependent mating disadvantage ultimately drives the transition to single-ploidy populations. However, comprehensive estimates of reproductive isolation among cytotypes and across multiple barriers are rare. We quantify the strength of isolation across multiple reproductive stages in a tetraploid–octoploid contact zone to understand the potential for coexistence. Methods Assortative mating due to flowering asynchrony, pollinator behaviour, morphological overlap, self-fertilization and gametic competition between tetraploid and octoploid Gladiolus communis in a contact zone in the Western Iberian Peninsula were assessed in natural and experimental populations to quantify reproductive isolation (RI) between cytotypes. Key Results Tetraploids and octoploids have a high degree of overlap in flowering time and similar floral morphology, and are visited by generalist insects without cytotype foraging preferences, resulting in weak pre-pollination RI (from 0.00 to 0.21). In contrast, post-pollination isolation resulting from gametic selection was a strong barrier to inter-cytotype mating, with ploidy composition in stigmatic pollen loads determining the levels of RI (from 0.54 to 1.00). Between-cytotype cross-incompatibility was relatively high (RI from 0.54 to 0.63) as was isolation acquired through self-pollination (RI of 0.59 in tetraploids and 0.39 in octoploids). Conclusions Total RI was high for both tetraploids (from 0.90 to 1.00) and octoploids (from 0.78 to 0.98). Such high rates of assortative mating will enable cytotype coexistence in mixed-ploidy populations by weakening the impacts of minority cytotype exclusion. This study reveals the key role of gametic selection in cytotype siring success and highlights the importance of comprehensive estimates across multiple reproductive barriers to understand cytotype interactions at contact zones.

scholarly journals Encounters in the ebb and flood: Knowing marine ecologies in the intertidal contact zone

2019 ◽  
Vol 2 (4) ◽  
pp. 761-780 ◽  
Author(s):  
Aurora Fredriksen
Keyword(s):  
Contact Zone ◽  
Ways Of Knowing ◽  
Tidal Energy ◽  
Small Scale ◽  
Bay Of Fundy ◽  
Contact Zones ◽  
Nonhuman Animals ◽  
Marine Wildlife

Shifting rhythmically between land and sea with the ebb and flood tides, shores are places where humans and nonhumans encounter one another in ambivalent relations of deep familiarity and enduring strangeness. In this article, I use the space of the intertidal contact zone to think through a series of uneven encounters between humans and marine wildlife that populate a dispute over tidal energy testing in the Bay of Fundy's Minas Passage. I trace two contact zones through which knowledge about marine wildlife in the Bay of Fundy is generated: first, the contact zone continually (re-)assembled through the encounters of small-scale and traditional fishers with marine wildlife, and second, the contact zone staged in remote encounters between marine scientists and marine wildlife. The article reflects on the role of bodies in and out of encounter in the different ways of knowing about marine wildlife in this case and considers ethical possibilities and limits of knowing through, versus without, contact with nonhuman animals in the intertidal contact zone.

Phenotypic differentiation of species from Aspergillus section Flavi on neutral red desiccated coconut agar

2014 ◽  
Vol 7 (3) ◽  
pp. 335-344 ◽  
Author(s):  
C.N. Ezekiel ◽  
M.C. Adetunji ◽  
O.O. Atanda ◽  
J.C. Frisvad ◽  
J. Houbraken ◽  
...  
Keyword(s):  
Morphological Differentiation ◽  
Aflatoxin Production ◽  
Neutral Red ◽  
Rapid Identification ◽  
Phenotypic Traits ◽  
Phenotypic Differentiation ◽  
Aspergillus Section Flavi ◽  
Aflatoxin B ◽  
The Relationship ◽  
Aspergillus Section

In order to facilitate easy and rapid identification of aflatoxin-producing Aspergillus species, the phenotypic traits of Aspergillus section Flavi isolates were examined on neutral red desiccated coconut agar (NRDCA). Phenotype variations in colony morphology and the relationship between colour/intensity of fluorescence and aflatoxin production were assessed. The isolates included 10 Aspergillus minisclerotigenes strains, 11 non-aflatoxigenic Aspergillus flavus L strains, 29 aflatoxigenic A. flavus L strains and 20 strains each of Aspergillus parasiticus and Aspergillus parvisclerotigenus. The NRDCA medium supported morphological differentiation of the four species based on colony features, conidia type and colour. In particular, the two very closely related minisclerotial species, A. minisclerotigenes and A. parvisclerotigenus, were clearly differentiated by their colony colour on NRDCA. All toxigenic isolates produced aflatoxins in the culture medium in varying quantities. Plates of aflatoxigenic A. flavus L strains fluoresced bluish purple/lavender around the colony on the obverse and pastel blue on the reverse side due to aflatoxin B production while those of A. minisclerotigenes, A. parasiticus and A. parvisclerotigenus fluoresced with a light blue or light turquoise ring around the colony on the obverse and light sky blue or cadet blue on the reverse side depending on the amount of aflatoxin B and G produced. The colour of fluorescence significantly correlated (r=0.95, P=0.001) with the type(s) of aflatoxins produced by the isolates. In addition, the concentration of aflatoxins significantly (r=0.92; P=0.001) influenced the intensity of fluorescence in the aflatoxin-producing species. NRDCA can therefore be used for the rapid identification of Aspergillus section Flavi species based on colonial characteristics, and grouping of species into B and B+G aflatoxin producers within 5 days thus obviating the need for chemical analysis of the culture.

scholarly journals New, Rare and Slavonized Graecisms and Their Role in Localization of Church Slavonic Texts

2018 ◽  
Author(s):  
Емилија Црвенковска
Keyword(s):  
Contact Zone ◽  
Spatial Localization ◽  
Precise Localization ◽  
Contact Zones ◽  
The Church

The paper provides overview of the destiny of some Old Church Slavonic/Church Slavonic manuscripts, as well as the issues related to their time and spatial localization. Special attention has been paid to the role of loanwords in localization of these texts, taking into consideration the different Slavonic and Non-Slavonic contact zones. In addition, the paper elaborates on some rare, new and Slavonized graecisms, entered after the return of the Church Slavonic literature at the Slavonic South, in Slavonic-Greek contact zone. This lexis can be usually found in hymnographic texts, in prophetologion, as well as in the commented psalter. Analysis of many properties shows that Slavonic translations or later redactions of these texts are created at the Ohrid Literary School, i.e. at the Slavonic southwest areal. Several graecisms which became part of the spoken and dialect language contribute to more precise localization. The question remains how certain graecisms can contribute to more precise localization of Church Slavonic texts, considering the fact that a certain lexical layer can originate from the archetype or from the protograph. It is possible that the lexical elements can be a result of the latter redaction.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

scholarly journals The underestimated role of the microphthalmia-associated transcription factor (MiTF) in normal and pathological haematopoiesis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alessia Oppezzo ◽  
Filippo Rosselli
Keyword(s):  
Stem Cells ◽  
Gene Networks ◽  
Bone Marrow Failure ◽  
Phenotypic Traits ◽  
Expression Of Genes ◽  
Specific Setting ◽  
Haematopoietic System ◽  
Abnormal Pigmentation ◽  
In Cells

AbstractHaematopoiesis, the process by which a restrained population of stem cells terminally differentiates into specific types of blood cells, depends on the tightly regulated temporospatial activity of several transcription factors (TFs). The deregulation of their activity or expression is a main cause of pathological haematopoiesis, leading to bone marrow failure (BMF), anaemia and leukaemia. TFs can be induced and/or activated by different stimuli, to which they respond by regulating the expression of genes and gene networks. Most TFs are highly pleiotropic; i.e., they are capable of influencing two or more apparently unrelated phenotypic traits, and the action of a single TF in a specific setting often depends on its interaction with other TFs and signalling pathway components. The microphthalmia-associated TF (MiTF) is a prototype TF in multiple situations. MiTF has been described extensively as a key regulator of melanocyte and melanoma development because it acts mainly as an oncogene. Mitf-mutated mice show a plethora of pleiotropic phenotypes, such as microphthalmia, deafness, abnormal pigmentation, retinal degeneration, reduced mast cell numbers and osteopetrosis, revealing a greater requirement for MiTF activity in cells and tissue. A growing amount of evidence has led to the delineation of key roles for MiTF in haematopoiesis and/or in cells of haematopoietic origin, including haematopoietic stem cells, mast cells, NK cells, basophiles, B cells and osteoclasts. This review summarizes several roles of MiTF in cells of the haematopoietic system and how MiTFs can impact BM development.

Characterizing spatial structures of larval fish assemblages at multiple scales in relation to environmental heterogeneity in the Strait of Georgia (British Columbia, Canada)

2018 ◽  
Vol 75 (11) ◽  
pp. 1902-1914 ◽  
Author(s):  
Lu Guan ◽  
John F. Dower ◽  
Pierre Pepin
Keyword(s):  
British Columbia ◽  
Environmental Heterogeneity ◽  
Multiple Scales ◽  
Larval Fish ◽  
Critical Role ◽  
Multiscale Approach ◽  
Spatial Structures ◽  
Strait Of Georgia ◽  
Medium Scale

Spatial structures of larval fish in the Strait of Georgia (British Columbia, Canada) were quantified in the springs of 2009 and 2010 to investigate linkages to environmental heterogeneity at multiple scales. By applying a multiscale approach, principal coordinate neighborhood matrices, spatial variability was decomposed into three predefined scale categories: broad scale (>40 km), medium scale (20∼40 km), and fine scale (<20 km). Spatial variations in larval density of the three dominant fish taxa with different early life histories (Pacific herring (Clupea pallasii), Pacific hake (Merluccius productus), and northern smoothtongue (Leuroglossus schmidti)) were mainly structured at broad and medium scales, with scale-dependent associations with environmental descriptors varying interannually and among species. Larval distributions in the central-southern Strait were mainly associated with salinity, temperature, and vertical stability of the top 50 m of the water column on the medium scale. Our results emphasize the critical role of local estuarine circulation, especially at medium spatial scale, in structuring hierarchical spatial distributions of fish larvae in the Strait of Georgia and suggest the role of fundamental differences in life-history traits in influencing the formation and maintenance of larval spatial structures.

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