Search results for "Pattern"
showing 10 items of 4203 documents
Evolutionary history and species delimitations:a case study of the hazel dormouse, Muscardinus avellanarius
2017
Robust identification of species and significant evolutionary units (ESUs) is essential to implement appropriate conservation strategies for endangered species. However, definitions of species or ESUs are numerous and sometimes controversial, which might lead to biased conclusions, with serious consequences for the management of endangered species. The hazel dormouse, an arboreal rodent of conservation concern throughout Europe is an ideal model species to investigate the relevance of species identification for conservation purposes. This species is a member of the Gliridae family, which is protected in Europe and seriously threatened in the northern part of its range. We assessed the exten…
Morphometrics and Cladistics: Measuring Phylogeny in the Sea Urchin Echinocardium
1996
A phylogenetic approach to the study of evolutionary patterns is based on taxic homologies (synapomorphies). In contrast, the recognition of evolutionary processes (namely heterochronies) involves analysis of the entire morphology. Recent developments in geometric morphometry permit analysis of morphological similarities grounded in operational homologies. Such morphometric techniques are explored (1) at the level of evolutionary processes, and (2) as a complement in exploration of phylogenetic relationships. To examplify this, we perform a two-part study of the ontogeny and phylogeny of the spatangoid sea urchin Echinocardium. First, a phylogenetic analysis of ten Recent species in the gen…
Variable crab camouflage patterns defeat search image formation.
2021
Understanding what maintains the broad spectrum of variation in animal phenotypes and how this influences survival is a key question in biology. Frequency dependent selection – where predators temporarily focus on one morph at the expense of others by forming a “search image” – can help explain this phenomenon. However, past work has never tested real prey colour patterns, and rarely considered the role of different types of camouflage. Using a novel citizen science computer experiment that presented crab “prey” to humans against natural backgrounds in specific sequences, we were able to test a range of key hypotheses concerning the interactions between predator learning, camouflage and mor…
Evolutionary Trends in the Mitochondrial Genome of Archaeplastida: How Does the GC Bias Affect the Transition from Water to Land?
2020
[EN] Among the most intriguing mysteries in the evolutionary biology of photosynthetic organisms are the genesis and consequences of the dramatic increase in the mitochondrial and nuclear genome sizes, together with the concomitant evolution of the three genetic compartments, particularly during the transition from water to land. To clarify the evolutionary trends in the mitochondrial genome of Archaeplastida, we analyzed the sequences from 37 complete genomes. Therefore, we utilized mitochondrial, plastidial and nuclear ribosomal DNA molecular markers on 100 species of Streptophyta for each subunit. Hierarchical models of sequence evolution were fitted to test the heterogeneity in the base…
Evaluating responses to temperature during pre-metamorphosis and carry-over effects at post-metamorphosis in the wood tiger moth (Arctia plantaginis)
2019
Insect metamorphosis is one of the most recognized processes delimiting transitions between phenotypes. It has been traditionally postulated as an adaptive process decoupling traits between life stages, allowing evolutionary independence of pre- and post-metamorphic phenotypes. However, the degree of autonomy between these life stages varies depending on the species and has not been studied in detail over multiple traits simultaneously. Here, we reared full-sib larvae of the warningly coloured wood tiger moth ( Arctia plantaginis ) in different temperatures and examined their responses for phenotypic (melanization change, number of moults), gene expression (RNA-seq and qPCR of candidate ge…
The current and future state of animal coloration research
2017
Animal colour patterns are a model system for understanding evolution because they are unusually accessible for study and experimental manipulation. This is possible because their functions are readily identifiable. In this final paper of the symposium we provide a diagram of the processes affecting colour patterns and use this to summarize their functions and put the other papers in a broad context. This allows us to identify significant ‘holes’ in the field that only become obvious when we see the processes affecting colour patterns, and their interactions, as a whole. We make suggestions about new directions of research that will enhance our understanding of both the evolution of colour …
Inheritance patterns of photoperiodic diapause induction inLeptinotarsa decemlineata
2016
Photoperiod is a reliable indicator of season and an important cue that many insects use for phenological synchronization. Undergoing range expansion insects can face a change in the local photoperiod to which they need to resynchronize. Rapid range expansion can be associated with rapid photoperiodic adaptation, which can be associated with intense selection on strongly heritable polygenic traits. Alternatively, it is proposed that, in insects with an XO sex-determination system, genes with large effect residing on the sex chromosome could drive photoperiodic adaptation because the gene or genes are exposed to selection in the sex carrying only a single X-chromosome. The present study seek…
Mechanisms of Defence to Pathogens : Biochemistry and Physiology
2014
SPE IPM; International audience; Plant defences comprise both pre-existing barriers as well as defences induced upon perception of pathogen-associated molecular patterns (PAMPs) or microbe-associated molecular patterns (MAMPs) or molecules produced from damage as a result of infection (damage-associated molecular patterns (DAMPs)). This chapter focuses on the induced mechanisms of defence. The inducibility of phytoalexin biosynthesis has probably been favoured in the course of evolution by biological constraints such as metabolic costs and functional side-effects associated with chemical defence. Historically, the term ‘hypersensitive’ refers to the rapid and localized cell death induced in…
Evolutionary population dynamics
2005
The interface between the evolution of life history traits and population dynamics in temporally and spatially variable environments is the topic of this chapter. Thus, the frame for the life history processes is set by spatial and temporal fluctuations in population density. Here, we will focus primarily on modes of reproduction and we are especially interested in whether alternative reproductive strategies can co-exist in a population. We show that spatially structured populations may allow co-existence of various life history strategies that do not easily co-exist in a nonstructured environment. Also, intrinsic and external temporal fluctuations in the environment tend to enhance polymor…
Drosophila Evolution over Space and Time (DEST) - A New Population Genomics Resource
2021
Abstract Drosophila melanogaster is a leading model in population genetics and genomics, and a growing number of whole-genome datasets from natural populations of this species have been published over the last 20 years. A major challenge is the integration of these disparate datasets, often generated using different sequencing technologies and bioinformatic pipelines, which hampers our ability to address questions about the evolution and population structure of this species. Here we address these issues by developing a bioinformatics pipeline that maps pooled sequencing (Pool-Seq) reads from D. melanogaster to a hologenome consisting of fly and symbiont genomes and estimates allele frequenc…