Unparalleled rates of species diversification in Europe Valente, Luis M.; Savolainen, Vincent; Vargas, Pablo
Proceedings - Royal Society. Biological sciences/Proceedings - Royal Society. Biological Sciences,
05/2010, Letnik:
277, Številka:
1687
Journal Article
Recenzirano
Odprti dostop
The most rapid species radiations have been reported from ‘evolutionary laboratories’, such as the Andes and the Cape of South Africa, leading to the prevailing view that diversification elsewhere ...has not been as dramatic. However, few studies have explicitly assessed rates of diversification in northern regions such as Europe. Here, we show that carnations (Dianthus, Caryophyllaceae), a well-known group of plants from temperate Eurasia, have diversified at the most rapid rate ever reported in plants or terrestrial vertebrates. Using phylogenetic methods, we found that the majority of species of carnations belong to a lineage that is remarkably species-rich in Europe, and arose at the rate of 2.2–7.6 species per million years. Unlike most previous studies that have inferred rates of diversification in young diverse groups, we use a conservative approach throughout that explicitly incorporates the uncertainties associated with phylogenetic inference, molecular dating and incomplete taxon sampling. We detected a shift in diversification rates of carnations coinciding with a period of increase in climatic aridity in the Pleistocene, suggesting a link between climate and biodiversity. This explosive radiation suggests that Europe, the continent with the world's best-studied flora, has been underestimated as a cradle of recent and rapid speciation.
The effects of island ontogeny on species diversity and phylogeny Valente, Luis M.; Etienne, Rampal S.; Phillimore, Albert B.
Proceedings - Royal Society. Biological sciences/Proceedings - Royal Society. Biological Sciences,
06/2014, Letnik:
281, Številka:
1784
Journal Article
Recenzirano
Odprti dostop
A major goal of island biogeography is to understand how island communities are assembled over time. However, we know little about the influence of variable area and ecological opportunity on island ...biotas over geological timescales. Islands have limited life spans, and it has been posited that insular diversity patterns should rise and fall with an island's ontogeny. The potential of phylogenies to inform us of island ontogenetic stage remains unclear, as we lack a phylogenetic framework that focuses on islands rather than clades. Here, we present a parsimonious island-centric model that integrates phylogeny and ontogeny into island biogeography and can incorporate a negative feedback of diversity on species origination. This framework allows us to generate predictions about species richness and phylogenies on islands of different ages. We find that peak richness lags behind peak island area, and that endemic species age increases with island age on volcanic islands. When diversity negatively affects rates of immigration and cladogenesis, our model predicts speciation slowdowns on old islands. Importantly, we find that branching times of in situ radiations can be informative of an island's ontogenetic stage. This novel framework provides a quantitative means of uncovering processes responsible for island biogeography patterns using phylogenies.
The study of islands as model systems has played an important role in the development of evolutionary and ecological theory. The 50th anniversary of MacArthur and Wilson's (December 1963) article, ...‘An equilibrium theory of insular zoogeography’, was a recent milestone for this theme. Since 1963, island systems have provided new insights into the formation of ecological communities. Here, building on such developments, we highlight prospects for research on islands to improve our understanding of the ecology and evolution of communities in general. Throughout, we emphasise how attributes of islands combine to provide unusual research opportunities, the implications of which stretch far beyond islands. Molecular tools and increasing data acquisition now permit re‐assessment of some fundamental issues that interested MacArthur and Wilson. These include the formation of ecological networks, species abundance distributions, and the contribution of evolution to community assembly. We also extend our prospects to other fields of ecology and evolution – understanding ecosystem functioning, speciation and diversification – frequently employing assets of oceanic islands in inferring the geographic area within which evolution has occurred, and potential barriers to gene flow. Although island‐based theory is continually being enriched, incorporating non‐equilibrium dynamics is identified as a major challenge for the future.
Tracer diffusion coefficients obtained from the Taylor dispersion technique at 25.0 °C were measured to study the influence of sodium, ammonium and magnesium salts at 0.01 and 0.1 mol dm
on the ...transport behavior of sodium hyaluronate (NaHy, 0.1%). The selection of these salts was based on their position in Hofmeister series, which describe the specific influence of different ions (cations and anions) on some physicochemical properties of a system that can be interpreted as a salting-in or salting-out effect. In our case, in general, an increase in the ionic strength (i.e., concentrations at 0.01 mol dm
) led to a significant decrease in the limiting diffusion coefficient of the NaHy 0.1%, indicating, in those circumstances, the presence of salting-in effects. However, the opposite effect (salting-out) was verified with the increase in concentration of some salts, mainly for NH
SCN at 0.1 mol dm
. In this particular salt, the cation is weakly hydrated and, consequently, its presence does not favor interactions between NaHy and water molecules, promoting, in those circumstances, less resistance to the movement of NaHy and thus to the increase of its diffusion (19%). These data, complemented by viscosity measurements, permit us to have a better understanding about the effect of these salts on the transport behaviour of NaHy.
The interactions between DNA and a number of different cationic surfactants, differing in headgroup polarity, were investigated by electric conductivity measurements and fluorescence microscopy. It ...was observed that, the critical association concentration (cac), characterizing the onset of surfactant binding to DNA, does not vary significantly with the architecture of the headgroup. However, comparing with the critical micelle concentration (cmc) in the absence of DNA, it can be inferred that the micelles of a surfactant with a simple quaternary ammonium headgroup are much more stabilized by the presence of DNA than those of surfactants with hydroxylated head-groups. In line with previous studies of polymer−surfactant association, the cac does not vary significantly with either the DNA concentration or its chain length. On the other hand, a novel observation is that the cac is much lower when DNA is denaturated and in the single-stranded conformation, than for the double-helix DNA. This is contrary to expectation for a simple electrostatically driven association. Thus previous studies of polyelectrolyte−surfactant systems have shown that the cac decreases strongly with increasing linear charge density of the polyion. Since double-stranded DNA (dsDNA) has twice as large linear charge density as single-stranded DNA (ssDNA), the stronger binding in the latter case indicates an important role of nonelectrostatic effects. Both a higher flexibility of ssDNA and a higher hydrophobicity due to the exposed bases are found to play a role, with the hydrophobic interaction argued to be more important. The significance of hydrophobic DNA−surfactant interaction is in line with other observations. The significance of nonelectrostatic effects is also indicated in significant differences in cac between different surfactants for ssDNA but not for dsDNA. For lower concentrations of DNA, the conductivity measurements presented an “anomalous” feature, i.e., a second inflection point for surfactant concentrations below the cac; this feature was not displayed at higher concentrations of DNA. The effect is attributed to the presence of a mixture of ss- and dsDNA molecules. Thus the stability of dsDNA is dependent on a certain ion atmosphere; at lower ion concentrations the electrostatic repulsions between the DNA strands become too strong compared to the attractive interactions, and there is a dissociation into the individual strands. Fluorescence microscopy studies, performed at much lower DNA concentrations, demonstrated a transformation of dsDNA from an extended “coil” state to a compact “globule” condition, with a broad concentration region of coexistence of coils and globules. The onset of DNA compaction coincides roughly with the cac values obtained from conductivity measurements. This is in line with the observed independence of cac on the DNA concentration, together with the assumption that the onset of binding corresponds to an initiation of DNA compaction. No major changes in either the onset of compaction or complete compaction were observed as the surfactant headgroup was made more polar.
Display omitted
► Most species of Carex belong to non-Siderosicta Carex clade which crown node dates to the Late Eocene and Oligocene. ► Non-Siderosicta Carex clade underwent a shift in ...diversification rates, during a global cooling and drying period. ► This shift in diversification rates fits with a transition in diploid chromosome number. ► Climate change, the presence of perigynium and chromosome rearrangements may explain the hyper-diversity of Carex.
The sedge family (Cyperaceae: Poales; ca. 5600 spp.) is a hyperdiverse cosmopolitan group with centres of species diversity in Africa, Australia, eastern Asia, North America, and the Neotropics. Carex, with ca. 40% of the species in the family, is one of the most species-rich angiosperm genera and the most diverse in temperate regions of the Northern Hemisphere, making it atypical among plants in that it inverts the latitudinal gradient of species richness. Moreover, Carex exhibits high rates of chromosome rearrangement via fission, fusion, and translocation, which distinguishes it from the rest of the Cyperaceae. Here, we use a phylogenetic framework to examine how the onset of contemporary temperate climates and the processes of chromosome evolution have influenced the diversification dynamics of Carex. We provide estimates of diversification rates and map chromosome transitions across the evolutionary history of the main four clades of Carex. We demonstrate that Carex underwent a shift in diversification rates sometime between the Late Eocene and the Oligocene, during a global cooling period, which fits with a transition in diploid chromosome number. We suggest that adaptive radiation to novel temperate climates, aided by a shift in the mode of chromosome evolution, may explain the large-scale radiation of Carex and its latitudinal pattern of species richness.
Skeletal muscle growth and flesh quality were evaluated in Senegalese sole fed plant protein (PP) diets. A control fish meal-based diet (FM) was compared with three isonitrogenous (54%) and ...isolipidic (9%) diets with increasing levels of PP blends (50% PP50, 75% PP75 and 100% PP100). By the end of the experiment sole fed PP50 and PP75 had a body length similar to the CTR (25cm), but fish fed PP100 were significantly smaller (23cm). Total FM replacement (PP100) resulted in significantly smaller muscle cross sectional area mainly due to a decrease in the muscle fibre size as the total number of fibres did not vary significantly among treatments. The dietary incorporation of PP significantly reduced the expression of several key genes involved in myogenesis and muscle growth (mrf4, fgf6, myhc and mylc2). Fillet texture was affected by the total substitution of FM. Fish fed PP100 diet had a significantly higher modulus of elasticity (lower flesh stiffness) compared with the other groups. Muscle fibre size was moderately related (r=0.573) to the modulus of elasticity and positively correlated with the expression of lysyl oxidase (r=0.495). Muscle cellularity changes were not associated with the expression of texture-related genes (capn2, ctsb, ctsd), since no significant differences were observed among diets. The present results point towards a modulation of the expression of several muscle growth related genes by increasing levels of PP sources that alter muscle cellularity and textural properties of Senegalese sole when total FM is replaced by PP.
The biological basis through which sustainable and practical plant protein diets (PP) affect flesh texture determinants is extremely scarce so the present results will be valuable to the aquafeed industry, fish producers and final consumers. This study clearly shows that PP diets reduced expression of several key genes involved in myogenesis and muscle growth and can hence affect fish growth potential at long term. This study identifies useful markers that correlated well with muscle cellularity and muscle growth and can be further used to select the most appropriate diets for a fish species.
•Senegalese sole can effectively use diets with PP sources up to 75% of fish meal replacement.•Total FM substitution by PP (PP100) decreased final body size and muscle cross sectional area (CSA).•Smaller CSA in fish fed PP100 was associated with smaller fibre size.•PP diets reduced expression of several key genes involved in myogenesis and muscle growth.•Decreased stiffness (higher modulus of elasticity) in PP100 fillets was partially related with cell size reduction.
Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at ...a dynamic equilibrium, but for remote islands, such as Hawaii or Galápagos, this idea remains untested. Here, we reconstruct the temporal accumulation of terrestrial bird species of the Galápagos using a novel phylogenetic method that estimates rates of biota assembly for an entire community. We show that species richness on the archipelago is in an ascending phase and does not tend towards equilibrium. The majority of the avifauna diversifies at a slow rate, without detectable ecological limits. However, Darwin's finches form an exception: they rapidly reach a carrying capacity and subsequently follow a coalescent‐like diversification process. Together, these results suggest that avian diversity of remote islands is rising, and challenge the mutual exclusivity of the non‐equilibrium and equilibrium ecological paradigms.
Guenons (tribe Cercopithecini) are one of the most diverse groups of primates. They occupy all of sub-Saharan Africa and show great variation in ecology, behavior, and morphology. This variation led ...to the description of over 60 species and subspecies. Here, using next-generation DNA sequencing (NGS) in combination with targeted DNA capture, we sequenced 92 mitochondrial genomes from museum-preserved specimens as old as 117 years. We infer evolutionary relationships and estimate divergence times of almost all guenon taxa based on mitochondrial genome sequences. Using this phylogenetic framework, we infer divergence dates and reconstruct ancestral geographic ranges. We conclude that the extraordinary radiation of guenons has been a complex process driven by, among other factors, localized fluctuations of African forest cover. We find incongruences between phylogenetic trees reconstructed from mitochondrial and nuclear DNA sequences, which can be explained by either incomplete lineage sorting or hybridization. Furthermore, having produced the largest mitochondrial DNA data set from museum specimens, we document how NGS technologies can "unlock" museum collections, thereby helping to unravel the tree-of-life.
Dietary inclusion of IMTA-cultivated
Gracilaria vermiculophylla
was evaluated in rainbow trout. Growth and feed efficiency were determined in fish fed 0 % (CTRL), 5 % (G5), and 10 % (G10) of the red ...seaweed for 91 days. Carotenoid concentration (skin and muscle), immunological parameters, and intestinal morphology were also evaluated. G10 group showed the lowest final body weight, with feed and protein efficiency ratios being significantly lower than the CTRL. Although protein intake was similar among groups, G10 diet induced the lowest protein retention and gain probably due to its smallest intestine diameter and lowest
villi
height. Fish fed G10 diet displayed higher carotenoid content in the skin (16.7 μg g
−1
) when compared with the CTRL group, but a lower concentration was registered in the flesh (0.23 μg g
−1
). Instrumental color showed that fillets were more luminous (
L
*), less yellowish (
b
*), and more reddish (a*) with seaweed inclusion and the lowest chrome intensity (
C
*) in the G10 group confirmed the lowest muscle carotenoid content in these fish. G5 diet enhanced the innate immune response of rainbow trout inducing the highest peroxidase, alternative complement (ACH50), and lysozyme activities. The inclusion of
Gracilaria
meal in diets for rainbow trout is possible up to 5 %, but a higher inclusion level impairs growth.
PDF
