scholarly journals Toxin expression in snake venom evolves rapidly with constant shifts in evolutionary rates

2020 ◽  
Vol 287 (1926) ◽  
pp. 20200613 ◽  
Author(s):  
Agneesh Barua ◽  
Alexander S. Mikheyev
Keyword(s):  
Snake Venom ◽  
Adaptive Radiation ◽  
Prey Capture ◽  
Phenotypic Evolution ◽  
Venomous Snake ◽  
Rates Of Evolution ◽  
Key Innovation ◽  
Venom Evolution ◽  
Phenotypic Diversification ◽  
Key Innovations

Key innovations provide ecological opportunity by enabling access to new resources, colonization of new environments, and are associated with adaptive radiation. The most well-known pattern associated with adaptive radiation is an early burst of phenotypic diversification. Venoms facilitate prey capture and are widely believed to be key innovations leading to adaptive radiation. However, few studies have estimated their evolutionary rate dynamics. Here, we test for patterns of adaptive evolution in venom gene expression data from 52 venomous snake species. By identifying shifts in tempo and mode of evolution along with models of phenotypic evolution, we show that snake venom exhibits the macroevolutionary dynamics expected of key innovations. Namely, all toxin families undergo shifts in their rates of evolution, likely in response to changes in adaptive optima. Furthermore, we show that rapid-pulsed evolution modelled as a Lévy process better fits snake venom evolution than conventional early burst or Ornstein–Uhlenbeck models. While our results support the idea of snake venom being a key innovation, the innovation of venom chemistry lacks clear mechanisms that would lead to reproductive isolation and thus adaptive radiation. Therefore, the extent to which venom directly influences the diversification process is still a matter of contention.

scholarly journals Coevolution is linked with phenotypic diversification but not speciation in avian brood parasites

2015 ◽  
Vol 282 (1821) ◽  
pp. 20152056 ◽  
Author(s):  
Iliana Medina ◽  
Naomi E. Langmore
Keyword(s):  
Egg Size ◽  
Biological Diversity ◽  
Phenotypic Diversity ◽  
Arms Race ◽  
Phenotypic Evolution ◽  
Brood Parasites ◽  
Parasitic Species ◽  
Extinction Rates ◽  
Rates Of Evolution ◽  
Phenotypic Diversification

Coevolution is often invoked as an engine of biological diversity. Avian brood parasites and their hosts provide one of the best-known examples of coevolution. Brood parasites lay their eggs in the nests of other species, selecting for host defences and reciprocal counteradaptations in parasites. In theory, this arms race should promote increased rates of speciation and phenotypic evolution. Here, we use recently developed methods to test whether the three largest avian brood parasitic lineages show changes in rates of phenotypic diversity and speciation relative to non-parasitic lineages. Our results challenge the accepted paradigm, and show that there is little consistent evidence that lineages of brood parasites have higher speciation or extinction rates than non-parasitic species. However, we provide the first evidence that the evolution of brood parasitic behaviour may affect rates of evolution in morphological traits associated with parasitism. Specifically, egg size and the colour and pattern of plumage have evolved up to nine times faster in parasitic than in non-parasitic cuckoos. Moreover, cuckoo clades of parasitic species that are sympatric (and share similar host genera) exhibit higher rates of phenotypic evolution. This supports the idea that competition for hosts may be linked to the high phenotypic diversity found in parasitic cuckoos.

scholarly journals Rates of morphological evolution in Captorhinidae: An adaptive radiation of Permian herbivores

2017 ◽  
Author(s):  
Neil Brocklehurst
Keyword(s):  
Causal Relationship ◽  
Adaptive Radiation ◽  
Morphological Evolution ◽  
Morphological Characteristics ◽  
Terrestrial Ecosystems ◽  
Evolutionary Patterns ◽  
Evolutionary Innovation ◽  
Rates Of Evolution ◽  
Key Innovation ◽  
The Impact

The evolution of herbivory in early tetrapods was crucial in the establishment of terrestrial ecosystems, although it is so far unclear what effect this innovation had on the macro-evolutionary patterns observed within this clade. The clades which entered this under-filled region of ecospace might be expected to have experienced an “adaptive radiation”: an increase in rates of morphological evolution and speciation driven by the evolution of a key innovation. However such inferences are often circumstantial, being based on the coincidence of a rate shift with the origin of an evolutionary novelty. The conclusion of an adaptive radiation may be made more robust by examining the pattern of the evolutionary shift; if the evolutionary innovation coincides not only with a shift in rates of morphological evolution, but specifically in the morphological characteristics relevant to the ecological shift of interest, then one may more plausibly infer a causal relationship between the two. Here I examine the impact of diet evolution on rates of morphological change in one of the earliest tetrapod clades to evolve high-fibre herbivory: Captorhinidae. Using a method of calculating heterogeneity in rates of discrete character change across a phylogeny, it is shown that a significant increase in rates of evolution coincides with the transition to herbivory in captorhinids. Theherbivorous captorhinids also exhibit greater morphological disparity than their faunivorous relatives, indicating more rapid exploration of new regions of morphospace. As well as an increase in rates of evolution, there is a shift in the regions of the skeleton undergoing the most change; the character changes in the herbivorous lineages are concentrated in the manible and dentition. The fact that the increase in rates of evolution coincides with increased change in characters relating to food acquisition provides stronger evidence for a causal relationship between the herbivorous diet and the radiation event.

scholarly journals Rates of morphological evolution in Captorhinidae: an adaptive radiation of Permian herbivores

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3200 ◽  
Author(s):  
Neil Brocklehurst
Keyword(s):  
Causal Relationship ◽  
Adaptive Radiation ◽  
Morphological Evolution ◽  
Morphological Characteristics ◽  
Terrestrial Ecosystems ◽  
Evolutionary Patterns ◽  
Evolutionary Innovation ◽  
Rates Of Evolution ◽  
Key Innovation ◽  
The Impact

The evolution of herbivory in early tetrapods was crucial in the establishment of terrestrial ecosystems, although it is so far unclear what effect this innovation had on the macro-evolutionary patterns observed within this clade. The clades that entered this under-filled region of ecospace might be expected to have experienced an “adaptive radiation”: an increase in rates of morphological evolution and speciation driven by the evolution of a key innovation. However such inferences are often circumstantial, being based on the coincidence of a rate shift with the origin of an evolutionary novelty. The conclusion of an adaptive radiation may be made more robust by examining the pattern of the evolutionary shift; if the evolutionary innovation coincides not only with a shift in rates of morphological evolution, but specifically in the morphological characteristics relevant to the ecological shift of interest, then one may more plausibly infer a causal relationship between the two.Here I examine the impact of diet evolution on rates of morphological change in one of the earliest tetrapod clades to evolve high-fibre herbivory: Captorhinidae. Using a method of calculating heterogeneity in rates of discrete character change across a phylogeny, it is shown that a significant increase in rates of evolution coincides with the transition to herbivory in captorhinids. The herbivorous captorhinids also exhibit greater morphological disparity than their faunivorous relatives, indicating more rapid exploration of new regions of morphospace. As well as an increase in rates of evolution, there is a shift in the regions of the skeleton undergoing the most change; the character changes in the herbivorous lineages are concentrated in the mandible and dentition. The fact that the increase in rates of evolution coincides with increased change in characters relating to food acquisition provides stronger evidence for a causal relationship between the herbivorous diet and the radiation event.

scholarly journals Evidence for determinism in species diversification and contingency in phenotypic evolution during adaptive radiation

2012 ◽  
Vol 279 (1748) ◽  
pp. 4817-4826 ◽  
Author(s):  
Frank T. Burbrink ◽  
Xin Chen ◽  
Edward A. Myers ◽  
Matthew C. Brandley ◽  
R. Alexander Pyron
Keyword(s):  
Adaptive Radiation ◽  
New World ◽  
Morphological Evolution ◽  
Rapid Change ◽  
Phenotypic Evolution ◽  
Late Oligocene ◽  
Species Diversification ◽  
Continental Scale ◽  
Phenotypic Diversification ◽  
Time Periods

Adaptive radiation (AR) theory predicts that groups sharing the same source of ecological opportunity (EO) will experience deterministic species diversification and morphological evolution. Thus, deterministic ecological and morphological evolution should be correlated with deterministic patterns in the tempo and mode of speciation for groups in similar habitats and time periods. We test this hypothesis using well-sampled phylogenies of four squamate groups that colonized the New World (NW) in the Late Oligocene. We use both standard and coalescent models to assess species diversification, as well as likelihood models to examine morphological evolution. All squamate groups show similar early pulses of speciation, as well as diversity-dependent ecological limits on clade size at a continental scale. In contrast, processes of morphological evolution are not easily predictable and do not show similar pulses of early and rapid change. Patterns of morphological and species diversification thus appear uncoupled across these groups. This indicates that the processes that drive diversification and disparification are not mechanistically linked, even among similar groups of taxa experiencing the same sources of EO. It also suggests that processes of phenotypic diversification cannot be predicted solely from the existence of an AR or knowledge of the process of diversification.

Adaptive Radiation

2003 ◽  
Author(s):  
Mary Jane West-Eberhard
Keyword(s):  
Adaptive Radiation ◽  
Interspecific Variation ◽  
Ecological Diversification ◽  
Phenotypic Divergence ◽  
Key Innovation ◽  
Major Transition ◽  
Cocos Island ◽  
Phenotypic Diversification ◽  
Multicellular Organisms ◽  
And Behavior

Adaptive radiation is the simultaneous diversification of a lineage into numerous sublineages and specializations (Simpson, 1953a). All of the species of a radiation constitute a monophyletic group, and they often share some innovative trait or set of traits (sometimes called a key innovation—Liem, 1973) that is thought to have allowed the lineage to undergo a major transition, moving it into a previously unoccupied zone of opportunity exploited in different ways by different branches A radiation is a proliferation of variations on a phenotypic theme, accompanied by a proliferation of species. Adaptive radiations are a major feature of the evolution of life. Biologists describe radiations at all phylogenetic levels—the radiation of the eukaryotes, the radiation of multicellular organisms, the radiation of vertebrates, of birds, of ungulates, of dung beetles, of a particular species complex of fish. The concept of adaptive radiation usually includes both lineage branching (speciation) and phenotypic diversification (Schluter, 2000). Speciation and phenotypic diversification are obviously related phenomena: the genetic isolation associated with speciation promotes phenotypic divergence between populations (Mayr, 1963; Futuyma, 1987), and phenotypic divergence within populations (polymorphism and polyphenism) can promote speciation, as discussed in chapter 27, so the two phenomena must often occur together. It does not follow, however, that adaptive radiation and speciation are inevitably linked (see Turner, 1999). Adaptive radiation can occur without speciation, as in the multiple individual trophic specializations of Cocos Island finches (see below) or in the diversity of human careers. And speciation can occur with little adaptive (ecological) diversification. Polistes, a cosmopolitan genus of social wasps (Vespidae), contains more than 300 species that differ primarily in their social and sexual behavior, with relatively little interspecific variation in trophic morphology and behavior, diet, size and shape, or habitat (reviewed in Turillazzi and West- Eberhard, 1996). The possibility of socially or sexually selected radiations with little ecological diversification is a neglected topic that deserves attention, but I do not pursue it here.

scholarly journals Do key innovations unlock diversification? A case-study on the morphological and ecological impact of pharyngognathy in acanthomorph fishes

2020 ◽  
Vol 66 (5) ◽  
pp. 575-588
Author(s):  
Olivier Larouche ◽  
Jennifer R Hodge ◽  
Laura R V Alencar ◽  
Benjamin Camper ◽  
Danielle S Adams ◽  
...  
Keyword(s):  
Ecological Impact ◽  
Phenotypic Evolution ◽  
Intrinsic Factors ◽  
Evolutionary Origins ◽  
Specific Effects ◽  
Key Innovation ◽  
Speciation Rates ◽  
The Impact ◽  
Key Innovations

Abstract Key innovations may allow lineages access to new resources and facilitate the invasion of new adaptive zones, potentially influencing diversification patterns. Many studies have focused on the impact of key innovations on speciation rates, but far less is known about how they influence phenotypic rates and patterns of ecomorphological diversification. We use the repeated evolution of pharyngognathy within acanthomorph fishes, a commonly cited key innovation, as a case study to explore the predictions of key innovation theory. Specifically, we investigate whether transitions to pharyngognathy led to shifts in the rate of phenotypic evolution, as well as shifts and/or expansion in the occupation of morphological and dietary space, using a dataset of 8 morphological traits measured across 3,853 species of Acanthomorpha. Analyzing the 6 evolutionarily independent pharyngognathous clades together, we found no evidence to support pharyngognathy as a key innovation; however, comparisons between individual pharyngognathous lineages and their sister clades did reveal some consistent patterns. In morphospace, most pharyngognathous clades cluster in areas that correspond to deeper-bodied morphologies relative to their sister clades, whereas occupying greater areas in dietary space that reflects a more diversified diet. Additionally, both Cichlidae and Labridae exhibited higher univariate rates of phenotypic evolution compared with their closest relatives. However, few of these results were exceptional relative to our null models. Our results suggest that transitions to pharyngognathy may only be advantageous when combined with additional ecological or intrinsic factors, illustrating the importance of accounting for lineage-specific effects when testing key innovation hypotheses. Moreover, the challenges we experienced formulating informative comparisons, despite the ideal evolutionary scenario of multiple independent evolutionary origins of pharyngognathous clades, illustrates the complexities involved in quantifying the impact of key innovations. Given the issues of lineage specific effects and rate heterogeneity at macroevolutionary scales we observed, we suggest a reassessment of the expected impacts of key innovations may be warranted.

scholarly journals Rates of morphological evolution in Captorhinidae: An adaptive radiation of Permian herbivores

2017 ◽  
Author(s):  
Neil Brocklehurst
Keyword(s):  
Causal Relationship ◽  
Adaptive Radiation ◽  
Morphological Evolution ◽  
Morphological Characteristics ◽  
Terrestrial Ecosystems ◽  
Evolutionary Patterns ◽  
Evolutionary Innovation ◽  
Rates Of Evolution ◽  
Key Innovation ◽  
The Impact

The evolution of herbivory in early tetrapods was crucial in the establishment of terrestrial ecosystems, although it is so far unclear what effect this innovation had on the macro-evolutionary patterns observed within this clade. The clades which entered this under-filled region of ecospace might be expected to have experienced an “adaptive radiation”: an increase in rates of morphological evolution and speciation driven by the evolution of a key innovation. However such inferences are often circumstantial, being based on the coincidence of a rate shift with the origin of an evolutionary novelty. The conclusion of an adaptive radiation may be made more robust by examining the pattern of the evolutionary shift; if the evolutionary innovation coincides not only with a shift in rates of morphological evolution, but specifically in the morphological characteristics relevant to the ecological shift of interest, then one may more plausibly infer a causal relationship between the two. Here I examine the impact of diet evolution on rates of morphological change in one of the earliest tetrapod clades to evolve high-fibre herbivory: Captorhinidae. Using a method of calculating heterogeneity in rates of discrete character change across a phylogeny, it is shown that a significant increase in rates of evolution coincides with the transition to herbivory in captorhinids. Theherbivorous captorhinids also exhibit greater morphological disparity than their faunivorous relatives, indicating more rapid exploration of new regions of morphospace. As well as an increase in rates of evolution, there is a shift in the regions of the skeleton undergoing the most change; the character changes in the herbivorous lineages are concentrated in the manible and dentition. The fact that the increase in rates of evolution coincides with increased change in characters relating to food acquisition provides stronger evidence for a causal relationship between the herbivorous diet and the radiation event.

scholarly journals Biomechanical trade-offs bias rates of evolution in the feeding apparatus of fishes

2011 ◽  
Vol 279 (1732) ◽  
pp. 1287-1292 ◽  
Author(s):  
Roi Holzman ◽  
David C. Collar ◽  
Samantha A. Price ◽  
C. Darrin Hulsey ◽  
Robert C. Thomson ◽  
...  
Keyword(s):  
Genetic Factors ◽  
Morphological Evolution ◽  
The Body ◽  
Body Parts ◽  
Phenotypic Evolution ◽  
Genetic Constraints ◽  
Functional Systems ◽  
Rates Of Evolution ◽  
Trade Offs

Morphological diversification does not proceed evenly across the organism. Some body parts tend to evolve at higher rates than others, and these rate biases are often attributed to sexual and natural selection or to genetic constraints. We hypothesized that variation in the rates of morphological evolution among body parts could also be related to the performance consequences of the functional systems that make up the body. Specifically, we tested the widely held expectation that the rate of evolution for a trait is negatively correlated with the strength of biomechanical trade-offs to which it is exposed. We quantified the magnitude of trade-offs acting on the morphological components of three feeding-related functional systems in four radiations of teleost fishes. After accounting for differences in the rates of morphological evolution between radiations, we found that traits that contribute more to performance trade-offs tend to evolve more rapidly, contrary to the prediction. While ecological and genetic factors are known to have strong effects on rates of phenotypic evolution, this study highlights the role of the biomechanical architecture of functional systems in biasing the rates and direction of trait evolution.

scholarly journals Intraspecific adaptive radiation: Competition, ecological opportunity, and phenotypic diversification within species

Evolution ◽  
2017 ◽  
Vol 71 (10) ◽  
pp. 2496-2509 ◽  
Author(s):  
Nicholas A. Levis ◽  
Ryan A. Martin ◽  
Kerry A. O'Donnell ◽  
David W. Pfennig
Keyword(s):  
Adaptive Radiation ◽  
Ecological Opportunity ◽  
Phenotypic Diversification

scholarly journals Fractionation of proteins from the venom of snake Ophiophagus hannah in Vietnam and their effects on adipogenesis in 3T3-L1 cells

2016 ◽  
Vol 14 (2) ◽  
pp. 225-230
Author(s):  
Nguyễn Thị Tuyết Nhung ◽  
Vũ Thị Hiền ◽  
Phạm Thị Hoa ◽  
Hà Thị Thu ◽  
Nguyễn Thị Hoa ◽  
...  
Keyword(s):  
Snake Venom ◽  
Lipid Droplets ◽  
Biological Effects ◽  
Potential Effect ◽  
Molecular Processes ◽  
Fat Cell ◽  
Medicinal Uses ◽  
Venomous Snake ◽  
Echis Carinatus ◽  
Ophiophagus Hannah

Snake venom is a mixture of different components with a great variety of biological effects. Some components in snake venom have been found to act specifically and potently on their targets. Unlike the venom of Naja naja, Echis carinatus, Vipera russellii which are widely used, there is little attention has been given to Ophiophagus hannah even this is the largest venomous snake in the world. In this study, using O. hannah venom collected at Dong Tam Snake Farm in Tien Giang Province, we have collected 4 protein fractions using membrane cut-off centrifugal filters, ie., YM100, YM50, YM 30, YM10 and YM3. Of the 4 fractions including (1) proteins from 3 kDa to smaller than 10 kDa, (2) proteins from 10 kDa to smaller than 30 kDa, (3) proteins from 30 kDa to smaller than 50 kDa and (4) proteins from 50 kDa to smaller 100 kDa, fraction 4 accounted for the highest proportion whereas fraction 3 is the lowest proportion. Following the demonstration of many medicinal uses of snake venom, potential effect of fraction 1 on obesity was examined. Although multiple molecular processes are involved in the progression of the disease, obesity can accompany increase in adipocyte size as a consequence of accumulation of lipid droplets within the fat cell, as well as increased number of adipocytes resulting from differentiation of precursor cells. In our study, two different concentrations of 1 μg/mL and 10 μg/mL proteins in fraction 1 were investigated for effectiveness on the 3T3-L1 cells differentiation and adipogenesis. The obtained results showed that, at the concentration of 10 μg/mL, this fraction inhibited the adipogenesis which have been shown by accumulation of lipid droplets within the 3T3-L1 cells.  Besides, at a concentration of 10 μg/mL, fraction 1 had no cytotoxic effect on cell viability of 3T3-L1 cells.

Sign in / Sign up

Export Citation Format

Share Document