The Experts below are selected from a list of 22074 Experts worldwide ranked by ideXlab platform
Alain Goriely - One of the best experts on this subject based on the ideXlab platform.
-
mechanical basis of morphogenesis and Convergent Evolution of spiny seashells
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Regis Chirat, Derek E Moulton, Alain GorielyAbstract:Convergent Evolution is a phenomenon whereby similar traits evolved independently in not closely related species, and is often interpreted in functional terms. Spines in mollusk seashells are classically interpreted as having repeatedly evolved as a defense in response to shell-crushing predators. Here we consider the morphogenetic process that shapes these structures and underlies their repeated emergence. We develop a mathematical model for spine morphogenesis based on the mechanical interaction between the secreting mantle edge and the calcified shell edge to which the mantle adheres during shell growth. It is demonstrated that a large diversity of spine structures can be accounted for through small variations in control parameters of this natural mechanical process. This physical mechanism suggests that Convergent Evolution of spines can be understood through a generic morphogenetic process, and provides unique perspectives in understanding the phenotypic Evolution of this second largest phylum in the animal kingdom.
Neelesh A Patankar - One of the best experts on this subject based on the ideXlab platform.
-
Convergent Evolution of mechanically optimal locomotion in aquatic invertebrates and vertebrates
PLOS Biology, 2015Co-Authors: Rahul Bale, Izaak D Neveln, Amneet Pal Singh Bhalla, Malcolm A Maciver, Neelesh A PatankarAbstract:Examples of animals evolving similar traits despite the absence of that trait in the last common ancestor, such as the wing and camera-type lens eye in vertebrates and invertebrates, are called cases of Convergent Evolution. Instances of Convergent Evolution of locomotory patterns that quantitatively agree with the mechanically optimal solution are very rare. Here, we show that, with respect to a very diverse group of aquatic animals, a mechanically optimal method of swimming with elongated fins has evolved independently at least eight times in both vertebrate and invertebrate swimmers across three different phyla. Specifically, if we take the length of an undulation along an animal’s fin during swimming and divide it by the mean amplitude of undulations along the fin length, the result is consistently around twenty. We call this value the optimal specific wavelength (OSW). We show that the OSW maximizes the force generated by the body, which also maximizes swimming speed. We hypothesize a mechanical basis for this optimality and suggest reasons for its repeated emergence through Evolution.
Graham Coop - One of the best experts on this subject based on the ideXlab platform.
-
Convergent Evolution During Local Adaptation to Patchy Landscapes.
PLOS Genetics, 2015Co-Authors: Peter L. Ralph, Graham CoopAbstract:Species often encounter, and adapt to, many patches of similar environmental conditions across their range. Such adaptation can occur through Convergent Evolution if different alleles arise in different patches, or through the spread of shared alleles by migration acting to synchronize adaptation across the species. The tension between the two reflects the constraint imposed on Evolution by the underlying genetic architecture versus how effectively selection and geographic isolation act to inhibit the geographic spread of locally adapted alleles. This paper studies the balance between these two routes to adaptation in a model of continuous environments with patchy selection pressures. We address the following questions: How long does it take for a novel allele to appear in a patch where it is locally adapted through mutation? Or, through migration from another, already adapted patch? Which is more likely to occur, as a function of distance between the patches? What population genetic signal is left by the spread of migrant alleles? To answer these questions we examine the family structure underlying migration–selection equilibrium surrounding an already adapted patch, treating those rare families that reach new patches as spatial branching processes. A main result is that patches further apart than a critical distance will likely evolve independent locally adapted alleles; this distance is proportional to the spatial scale of selection (σ/sm, where σ is the dispersal distance and s m is the selective disadvantage of these alleles between patches), and depends linearly on log(s m/μ), where μ is the mutation rate. This provides a way to understand the role of geographic separation between patches in promoting Convergent adaptation and the genomic signals it leaves behind. We illustrate these ideas using the Convergent Evolution of cryptic coloration in the rock pocket mouse, Chaetodipus intermedius, as an empirical example.
-
Convergent Evolution During Local Adaptation to Patchy Landscapes
bioRxiv, 2014Co-Authors: Peter L. Ralph, Graham CoopAbstract:Species often encounter, and adapt to, many patches of locally similar environmental conditions across their range. Such adaptation can occur through Convergent Evolution if different alleles arise and spread in different patches, or through the spread of shared alleles by migration acting to synchronize adaptation across the species. The tension between the two reflects the degree of constraint imposed on Evolution by the underlying genetic architecture versus how effectively selection and geographic isolation act to inhibit the geographic spread of locally adapted alleles. This paper studies a model of the balance between these two routes to adaptation in continuous environments with patchy selection pressures. We address the following questions: How long does it take for a novel, locally adapted allele to appear in a patch of habitat where it is favored through mutation? Or, through migration from another, already adapted patch? Which is more likely to occur, as a function of distance between the patches? How can we tell which has occurred, i.e. what population genetic signal is left by the spread of migrant alleles? To answer these questions we examine the family structure underlying migration--selection equilibrium surrounding an already adapted patch, in particular treating those rare families that reach new patches as spatial branching processes. This provides a way to understand the role of geographic separation between patches in promoting Convergent adaptation and the genomic signals it leaves behind. We illustrate these ideas using the Convergent Evolution of cryptic coloration in the rock pocket mouse, Chaetodipus intermedius, as an empirical example.
Andrew D Foote - One of the best experts on this subject based on the ideXlab platform.
-
Convergent Evolution of the genomes of marine mammals
Nature Genetics, 2015Co-Authors: Andrew D Foote, Gregg W C Thomas, Tomas Vinař, Jessica Alfoldi, Jixin Deng, Shannon Dugan, Margaret E Hunter, Vandita Joshi, Ziad KhanAbstract:Marine mammals from different mammalian orders share several phenotypic traits adapted to the aquatic environment and therefore represent a classic example of Convergent Evolution. To investigate Convergent Evolution at the genomic level, we sequenced and performed de novo assembly of the genomes of three species of marine mammals (the killer whale, walrus and manatee) from three mammalian orders that share independently evolved phenotypic adaptations to a marine existence. Our comparative genomic analyses found that Convergent amino acid substitutions were widespread throughout the genome and that a subset of these substitutions were in genes evolving under positive selection and putatively associated with a marine phenotype. However, we found higher levels of Convergent amino acid substitutions in a control set of terrestrial sister taxa to the marine mammals. Our results suggest that, whereas Convergent molecular Evolution is relatively common, adaptive molecular convergence linked to phenotypic convergence is comparatively rare.
Michael Tobler - One of the best experts on this subject based on the ideXlab platform.
-
Convergent Evolution of conserved mitochondrial pathways underlies repeated adaptation to extreme environments
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Ryan Greenway, Nick Barts, Chathurika Henpita, Anthony P Brown, Lenin Arias Rodriguez, Carlos Rodriguez M Pena, Sabine Arndt, Michael P Murphy, Lei Wu, Michael ToblerAbstract:Extreme environments test the limits of life; yet, some organisms thrive in harsh conditions. Extremophile lineages inspire questions about how organisms can tolerate physiochemical stressors and whether the repeated colonization of extreme environments is facilitated by predictable and repeatable Evolutionary innovations. We identified the mechanistic basis underlying Convergent Evolution of tolerance to hydrogen sulfide (H2S)—a toxicant that impairs mitochondrial function—across Evolutionarily independent lineages of a fish (Poecilia mexicana, Poeciliidae) from H2S-rich springs. Using comparative biochemical and physiological analyses, we found that mitochondrial function is maintained in the presence of H2S in sulfide spring P. mexicana but not ancestral lineages from nonsulfidic habitats due to Convergent adaptations in the primary toxicity target and a major detoxification enzyme. Genome-wide local ancestry analyses indicated that Convergent Evolution of increased H2S tolerance in different populations is likely caused by a combination of selection on standing genetic variation and de novo mutations. On a macroEvolutionary scale, H2S tolerance in 10 independent lineages of sulfide spring fishes across multiple genera of Poeciliidae is correlated with the Convergent modification and expression changes in genes associated with H2S toxicity and detoxification. Our results demonstrate that the modification of highly conserved physiological pathways associated with essential mitochondrial processes mediates tolerance to physiochemical stress. In addition, the same pathways, genes, and—in some instances—codons are implicated in H2S adaptation in lineages that span 40 million years of Evolution.
-
Convergent Evolution of reduced energy demands in extremophile fish.
PLOS ONE, 2017Co-Authors: Courtney N. Passow, Lenin Arias-rodriguez, Michael ToblerAbstract:Citation: Passow, C. N., Arias-Rodriguez, L., & Tobler, M. (2017). Convergent Evolution of reduced energy demands in extremophile fish. PLOS ONE, 12(10), e0186935. https://doi.org/10.1371/journal.pone.0186935
