Search results for "evolutionary"
showing 10 items of 4392 documents
Health and disease imprinted in the time variability of the human microbiome
2015
Human microbiota plays an important role in determining changes from health to disease. Increasing research activity is dedicated to understand its diversity and variability. We analyse 16S rRNA and whole genome sequencing (WGS) data from the gut microbiota of 97 individuals monitored in time. Temporal fluctuations in the microbiome reveal significant differences due to factors that affect the microbiota such as dietary changes, antibiotic intake, early gut development or disease. Here we show that a fluctuation scaling law describes the temporal variability of the system and that a noise-induced phase transition is central in the route to disease. The universal law distinguishes healthy fr…
De novogenome assembly of the land snailCandidula unifasciata(Mollusca: Gastropoda)
2021
AbstractAmong all molluscs, land snails are an economically and scientifically interesting group comprising edible species, alien species and agricultural pests. Yet, despite its high diversity, the number of whole genomes publicly available is still scarce. Here, we present the draft genome assembly of the land snailCandidula unifasciata, a widely distributed species along central Europe, which belongs to Geomitridae family, a group highly diversified in the Western-Palearctic region. We performed a whole genome sequencing, assembly and annotation of an adult specimen based on PacBio and Oxford Nanopore long read sequences as well as Illumina data. A genome of about 1.29 Gb was generated w…
The evolutionary history of HSA7/16 synteny in vertebrates: a critical interpretation of comparative cytogenetic and genome sequence data
2013
The current work is an in silico study of data from previous publications and genome browsers, on the origin of the human synteny HSA7a/16p. The molecular composition of the chromosomal segments identified as HSA7a/16 and 7b (free or differently associated) is not yet clear. This means that a syntenic association 7/16, which can be detected by an in situ hybridization (FISH) method in different taxa, may not necessarily correspond to those of the same association in different lineages. In silico research, together with comparative cytogenetics, have been applied in order to define the composition of the 7/16 syntenic association. These results allow a confident reconstruction of the synteni…
Molecular Phylogenetic Analyses in Court Trials
2010
Molecular phylogenetics allows reconstructing of the genealogy and evolutionary history of organisms from information on their nucleotide or amino acid sequences. When sequences are derived from very fast evolving organisms, such as ribonucleic acid (RNA) viruses, changes accumulate in a few days or weeks, thus allowing the reconstruction of very recent evolutionary events in the history of these populations. One such event is the transmission of one of these viruses, for instance human immunodeficiency virus (HIV) or hepatitis C virus (HCV), from an infected person to another. This occasionally results in a legal demand seeking for compensation and/or punishment for the transmitter. Hence,…
Temperature-dependence of spontaneous mutation rates
2020
Mutation is the source of genetic variation and the fundament of evolution. At the interphase of ecology and evolution, temperature has long been suggested to have a direct impact on realised spontaneous mutation rates. The question is whether mutation rates can be a species-specific constant under variable environmental conditions, such as variation of the ambient temperature. By combining mutation accumulation with whole genome sequencing in a multicellular organism, we provide empirical support to reject this null hypothesis. Instead mutation rates depend on temperature in a U-shaped manner with increasing rates towards both temperature extremes. This relation has important implications …
Function and evolution of vertebrate globins.
2014
Globins are haem-proteins that bind O2 and thus play an important role in the animal's respiration and oxidative energy production. However, globins may also have other functions such as the decomposition or production of NO, the detoxification of reactive oxygen species or intracellular signalling. In addition to the well-investigated haemoglobins and myoglobins, genome sequence analyses have led to the identification of six further globin types in vertebrates: androglobin, cytoglobin, globin E, globin X, globin Y and neuroglobin. Here, we review the present state of knowledge on the functions, the taxonomic distribution and evolution of vertebrate globins, drawing conclusions about the fu…
Mode and Rate of Growth in Ammonoids
1996
In this chapter we discuss the mode and rate of growth in ammonoids, focusing primarily on postembryonic growth. We first discuss the general mode of growth and then describe the ontogenetic sequence of growth stages. These stages are recognized on the basis of changes in morphology. For example, a graph of the increase in size of whorl width versus shell diameter in an individual reveals changes through ontogeny that pinpoint the end of one growth stage and the beginning of another. We next discuss the overall rate of growth through ontogeny and establish a generalized growth curve. In this discussion, we refer to other cephalopods whose rate of growth is known. Fluctuations in the rate of…
Disentangling canid howls across multiple species and subspecies: Structure in a complex communication channel
2016
Wolves, coyotes, and other canids are members of a diverse genus of top predators of considerable conservation and management interest. Canid howls are long-range communication signals, used both for territorial defence and group cohesion. Previous studies have shown that howls can encode individual and group identity. However, no comprehensive study has investigated the nature of variation in canid howls across the wide range of species. We analysed a database of over 2000 howls recorded from 13 different canid species and subspecies. We applied a quantitative similarity measure to compare the modulation pattern in howls from different populations, and then applied an unsupervised clusteri…
Publication Network Analysis of an Academic Family in Information Systems
2011
The study of scientific collaboration through network analysis can give interesting conclusions about the publication habits of a scientific community. Co-authorship networks represent scientific collaboration as a graph: nodes correspond to authors, edges between nodes mark joint publications (Newman 2001a,b). Scientific publishing is decentralized. Choices of co-authors and research topics are seldomly globally coordinated. Still, the structure of co-authorship networks is far from random. Co-authorship networks are governed by principles that are similar in other complex networks such as social networks (Wasserman and Faust 1994), networks of citations between scientific papers (Egghe an…
Importance of dispersal and thermal environment for mycorrhizal communities: lessons from Yellowstone National Park
2011
International audience; The relative importance of dispersal and niche restrictions remains a controversial topic in community ecology, especially for microorganisms that are often assumed to be ubiquitous. We investigated the impact of these factors for the community assembly of the root-symbiont arbuscular mycorrhizal fungi (AMF) by sampling roots from geothermal and nonthermal grasslands in Yellowstone National Park (YNP), followed by sequencing and RFLP of AMF ribosomal DNA. With the exception of an apparent generalist RFLP type closely related to Glomus intraradices, a distance-based redundancy analysis indicated that the AMF community composition correlated with soil pH or pH-driven c…