scholarly journals Radula diversification promotes ecomorph divergence in an adaptive radiation of freshwater snails

2020 ◽  
Author(s):  
Leon Hilgers ◽  
Stefanie Hartmann ◽  
Jobst Pfaender ◽  
Nora Lentge-Maaß ◽  
Thomas von Rintelen ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Complex Traits ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Freshwater Snail ◽  
Freshwater Snails ◽  
Trophic Specialization ◽  
Adaptive Diversification ◽  
Adaptive Radiations ◽  
Lineage Divergence

AbstractAdaptive diversification of complex traits plays a pivotal role for the evolution of organismal diversity. However, the underlying molecular mechanisms remain largely elusive. In the freshwater snail genus Tylomelania, adaptive radiations were likely promoted by trophic specialization via diversification of their key foraging organ, the radula. To investigate the molecular basis of radula diversification and its contribution to lineage divergence, we use pooled tissue-specific transcriptomes of two sympatric Tylomelania sarasinorum ecomorphs. We show that divergence in both gene expression and coding sequences is stronger between radula transcriptomes compared to mantle and foot transcriptomes. These findings support the hypothesis that diversifying selection on the radula is driving speciation in Tylomelania radiations. We also identify several candidate genes for radula divergence. Putative homologs of some candidates (hh, arx, gbb) also contributed to trophic specialization in cichlids and Darwin’s finches, indicating that some molecular pathways may be especially prone to adaptive diversification.

scholarly journals Cranial shape evolution in adaptive radiations of birds: comparative morphometrics of Darwin's finches and Hawaiian honeycreepers

2017 ◽  
Vol 372 (1713) ◽  
pp. 20150481 ◽  
Author(s):  
Masayoshi Tokita ◽  
Wataru Yano ◽  
Helen F. James ◽  
Arhat Abzhanov
Keyword(s):  
Adaptive Radiation ◽  
Molecular Mechanisms ◽  
Rapid Evolution ◽  
Oceanic Islands ◽  
Shape Variation ◽  
Skull Morphology ◽  
Darwin's Finches ◽  
Hawaiian Honeycreepers ◽  
Darwin’S Finches ◽  
Adaptive Radiations

Adaptive radiation is the rapid evolution of morphologically and ecologically diverse species from a single ancestor. The two classic examples of adaptive radiation are Darwin's finches and the Hawaiian honeycreepers, which evolved remarkable levels of adaptive cranial morphological variation. To gain new insights into the nature of their diversification, we performed comparative three-dimensional geometric morphometric analyses based on X-ray microcomputed tomography (µCT) scanning of dried cranial skeletons. We show that cranial shapes in both Hawaiian honeycreepers and Coerebinae (Darwin's finches and their close relatives) are much more diverse than in their respective outgroups, but Hawaiian honeycreepers as a group display the highest diversity and disparity of all other bird groups studied. We also report a significant contribution of allometry to skull shape variation, and distinct patterns of evolutionary change in skull morphology in the two lineages of songbirds that underwent adaptive radiation on oceanic islands. These findings help to better understand the nature of adaptive radiations in general and provide a foundation for future investigations on the developmental and molecular mechanisms underlying diversification of these morphologically distinguished groups of birds. This article is part of the themed issue ‘Evo-devo in the genomics era, and the origins of morphological diversity’.

scholarly journals Bridging the Process-Pattern Divide to Understand the Origins and Early Stages of Adaptive Radiation: A Review of Approaches With Insights From Studies of Anolis Lizards

2019 ◽  
Vol 111 (1) ◽  
pp. 33-42 ◽  
Author(s):  
James T Stroud ◽  
Jonathan B Losos
Keyword(s):  
Adaptive Radiation ◽  
Biological Diversity ◽  
Greater Antilles ◽  
Adaptive Diversification ◽  
Early Stages ◽  
Process Pattern ◽  
Alternative Approach ◽  
Adaptive Radiations ◽  
Underlying Processes ◽  
Radiation Research

Abstract Understanding the origins and early stages of diversification is one of the most elusive tasks in adaptive radiation research. Classical approaches, which aim to infer past processes from present-day patterns of biological diversity, are fraught with difficulties and assumptions. An alternative approach has been to study young clades of relatively few species, which may represent the putative early stages of adaptive radiation. However, it is difficult to predict whether those groups will ever reach the ecological and morphological disparity observed in the sorts of clades usually referred to as adaptive radiations, thereby making their utility in informing the early stages of such radiations uncertain. Caribbean Anolis lizards are a textbook example of an adaptive radiation; anoles have diversified independently on each of the 4 islands in the Greater Antilles, producing replicated radiations of phenotypically diverse species. However, the underlying processes that drove these radiations occurred 30–65 million years ago and so are unobservable, rendering major questions about how these radiations came to be difficult to tackle. What did the ancestral species of the anole radiation look like? How did new species arise? What processes drove adaptive diversification? Here, we review what we have learned about the cryptic early stages of adaptive radiation from studies of Anolis lizards, and how these studies have attempted to bridge the process-pattern divide of adaptive radiation research. Despite decades of research, however, fundamental questions linking eco-evolutionary processes to macroevolutionary patterns in anoles remain difficult to answer.

scholarly journals Molecular mechanisms underlying nuchal hump formation in dolphin cichlid, Cyrtocara moorii

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Laurène Alicia Lecaudey ◽  
Christian Sturmbauer ◽  
Pooja Singh ◽  
Ehsan Pashay Ahi
Keyword(s):  
Central America ◽  
Adaptive Radiation ◽  
Expression Profiling ◽  
Molecular Mechanisms ◽  
Soft Tissues ◽  
Molecular Level ◽  
Teleost Fishes ◽  
East African ◽  
Rapid Speciation ◽  
Adaptive Radiations

AbstractEast African cichlid fishes represent a model to tackle adaptive changes and their connection to rapid speciation and ecological distinction. In comparison to bony craniofacial tissues, adaptive morphogenesis of soft tissues has been rarely addressed, particularly at the molecular level. The nuchal hump in cichlids fishes is one such soft-tissue and exaggerated trait that is hypothesized to play an innovative role in the adaptive radiation of cichlids fishes. It has also evolved in parallel across lakes in East Africa and Central America. Using gene expression profiling, we identified and validated a set of genes involved in nuchal hump formation in the Lake Malawi dolphin cichlid, Cyrtocara moorii. In particular, we found genes differentially expressed in the nuchal hump, which are involved in controlling cell proliferation (btg3, fosl1a and pdgfrb), cell growth (dlk1), craniofacial morphogenesis (dlx5a, mycn and tcf12), as well as regulators of growth-related signals (dpt, pappa and socs2). This is the first study to identify the set of genes associated with nuchal hump formation in cichlids. Given that the hump is a trait that evolved repeatedly in several African and American cichlid lineages, it would be interesting to see if the molecular pathways and genes triggering hump formation follow a common genetic track or if the trait evolved in parallel, with distinct mechanisms, in other cichlid adaptive radiations and even in other teleost fishes.

Antennal transcriptome analysis and candidate olfactory genes in Crematogaster rogenhoferi

2021 ◽  
pp. 1-12
Author(s):  
Xiang Zhou ◽  
Jixing Guo ◽  
Mingxia Zhang ◽  
Chunxiu Bai ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Biological Control ◽  
Transcriptome Analysis ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Biological Control Agent ◽  
Control Agent ◽  
Vital Role ◽  
Neuron Membrane ◽  
Ionotropic Receptors ◽  
Soft Scale

Abstract Crematogaster rogenhoferi (Hymenoptera: Formicidae), an omnivorous ant, is one of the dominant predatory natural enemies of a soft scale pest, Parasaissetia nigra Nietner (Homoptera: Coccidae), and can effectively control P. nigra populations in rubber forests. Olfaction plays a vital role in the process of predation. However, the information about the molecular mechanism of olfaction-evoked behaviour in C. rogenhoferi is limited. In this study, we conducted antennal transcriptome analysis to identify candidate olfactory genes. We obtained 53,892 unigenes, 16,185 of which were annotated. Based on annotations, we identified 49 unigenes related to chemoreception, including four odourant-binding proteins, three chemosensory proteins, 37 odourant receptors, two odourant ionotropic receptors and three sensory neuron membrane proteins. This is the first report on the molecular basis of the chemosensory system of C. rogenhoferi. The findings provide a basis for elucidating the molecular mechanisms of the olfactory-related behaviours of C. rogenhoferi, which would facilitate a better application of C. rogenhoferi as a biological control agent.

scholarly journals Adaptive radiation and hybridization in Wallace's Dreamponds: evidence from sailfin silversides in the Malili Lakes of Sulawesi

2006 ◽  
Vol 273 (1598) ◽  
pp. 2209-2217 ◽  
Author(s):  
Fabian Herder ◽  
Arne W Nolte ◽  
Jobst Pfaender ◽  
Julia Schwarzer ◽  
Renny K Hadiaty ◽  
...  
Keyword(s):  
New Species ◽  
Adaptive Radiation ◽  
Introgressive Hybridization ◽  
Reticulate Evolution ◽  
Species Group ◽  
Potential Force ◽  
Major Interest ◽  
Key Factor ◽  
Adaptive Radiations ◽  
Malili Lakes

Adaptive radiations are extremely useful to understand factors driving speciation. A challenge in speciation research is to distinguish forces creating novelties and those relevant to divergence and adaptation. Recently, hybridization has regained major interest as a potential force leading to functional novelty and to the genesis of new species. Here, we show that introgressive hybridization is a prominent phenomenon in the radiation of sailfin silversides (Teleostei: Atheriniformes: Telmatherinidae) inhabiting the ancient Malili Lakes of Sulawesi, correlating conspicuously with patterns of increased diversity. We found the most diverse lacustrine species-group of the radiation to be heavily introgressed by genotypes originating from streams of the lake system, an effect that has masked the primary phylogenetic pattern of the flock. We conclude that hybridization could have acted as a key factor in the generation of the flock's spectacular diversity. To our knowledge, this is the first empirical evidence for massive reticulate evolution within a complex animal radiation.

Shedding new light on the regulation of complementary chromatic adaptation

2008 ◽  
Vol 3 (4) ◽  
pp. 351-358 ◽  
Author(s):  
Beronda Montgomery
Keyword(s):  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Cellular Morphology ◽  
Chromatic Adaptation ◽  
Natural Environments ◽  
Complementary Chromatic Adaptation ◽  
Light Sensing ◽  
Central Elements ◽  
Over 40 Years

AbstractComplementary chromatic adaptation (CCA) is a light-dependent acclimation process that occurs in cyanobacteria and likely is related to increased fitness of these organisms in natural environments. Although CCA has been studied for over 40 years, significant advances in our understanding of the molecular foundations of CCA are still emerging. In this minireview, I explore recently reported developments that include novel insights into the molecular mechanisms utilized in the photoregulation of pigmentation and the molecular basis of light-dependent changes in cellular morphology, which are central elements of the process of CCA. I also discuss future avenues of study that are expected to lead to additional progress in our understanding of CCA and our general appreciation of light sensing and photomorphogenesis in cyanobacteria.

scholarly journals Molecular basis of disregulation of programmed lymphocytes’ death in chronic viral infection

2006 ◽  
Vol 5 (2) ◽  
pp. 23-34
Author(s):  
V. V. Novitsky ◽  
N. V. Ryazantseva ◽  
O. B. Zhoukova
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Viral Infection ◽  
Immune Cells ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Recent Literature ◽  
Chronic Viral Infection ◽  
Persistent Viruses

The review analyses information from recent literature and results of the authors’ own investigations concerning imbalance of programmed cell death in forming chronic viral infection. Molecular mechanisms of apoptosis modulation of immune cells by persistent viruses are discussed in the article.

scholarly journals Public-good driven release of heterogeneous resources leads to genotypic diversification of an isogenic yeast population in melibiose.

2021 ◽  
Author(s):  
Anjali Mahilkar ◽  
Phaniendra Alugoju ◽  
Vijendra Kavatalkar ◽  
Rajeshkannan E. ◽  
Jayadeva Bhat ◽  
...  
Keyword(s):  
Carbon Source ◽  
Public Good ◽  
Molecular Basis ◽  
Model System ◽  
Microbial Populations ◽  
Adaptive Diversification ◽  
E Coli ◽  
Hydrolysis Of ◽  
Convenient Model ◽  
Heterogeneous Resources

Adaptive diversification of an isogenic population, and its molecular basis has been a subject of a number of studies in the last few years. Microbial populations offer a relatively convenient model system to study this question. In this context, an isogenic population of bacteria (E. coli, B. subtilis, and Pseudomonas) has been shown to lead to genetic diversification in the population, when propagated for a number of generations. This diversification is known to occur when the individuals in the population have access to two or more resources/environments, which are separated either temporally or spatially. Here, we report adaptive diversification in an isogenic population of yeast, S. cerevisiae, when propagated in an environment containing melibiose as the carbon source. The diversification is driven due to a public good, enzyme α-galactosidase, leading to hydrolysis of melibiose into two distinct resources, glucose and galactose. The diversification is driven by a mutations at a single locus, in the GAL3 gene in the GAL/MEL regulon in the yeast.

scholarly journals The fog of genetics: Known unknowns and unknown unknowns in the genetics of complex traits and diseases

2019 ◽  
Author(s):  
João Pedro de Magalhães ◽  
Jingwei Wang
Keyword(s):  
Genetic Variability ◽  
Genetic Variants ◽  
Genetic Information ◽  
Complex Traits ◽  
Drug Targets ◽  
Molecular Mechanisms ◽  
Genetic Associations ◽  
Missing Heritability ◽  
Genome Space ◽  
Known Unknowns

AbstractAssociating genetic variants with phenotypes is not only important to understand the underlying biology but also to identify potential drug targets for treating diseases. It is widely accepted that for most complex traits many associations remain to be discovered, the so-called “missing heritability.” Yet missing heritability can be estimated, it is a known unknown, and we argue is only a fraction of the unknowns in genetics. The majority of possible genetic variants in the genome space are either too rare to be detected or even entirely absent from populations, and therefore do not contribute to estimates of phenotypic or genetic variability. We call these unknown unknowns in genetics the “fog of genetics.” Using data from the 1000 Genomes Project we then show that larger genes with greater genetic diversity are more likely to be associated with human traits, demonstrating that genetic associations are biased towards particular types of genes and that the genetic information we are lacking about traits and diseases is potentially immense. Our results and model have multiple implications for how genetic variability is perceived to influence complex traits, provide insights on molecular mechanisms of disease and for drug discovery efforts based on genetic information.

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