Search results for "Phylogenetics"

Molecular phylogeny of Metazoa (animals): monophyletic origin.

1995

The phylogenetic relationships within the kingdom Animalia (Metazoa) have long been questioned. Focusing on the lowest eukaryotic multicellular organisms, the metazoan phylum Porifera (sponges), it remained unsolved if they evolved multicellularity independently from a separate protist lineage (polyphyly of animals) of derived from the same protist group as the other animal phyla (monophyly). After having analyzed genes typical for multicellularity (adhesion molecules/receptors and a nuclear receptor), we present evidence that Porifera should be placed in the kingdom Animalia. We therefore suggest a monophyletic origin for all animals.

Origin and evolution of arthropod hemocyanins and related proteins.

2002

Arthropod hemocyanins are large, multimeric, (n x 6) copper-containing proteins that deliver oxygen in the haemolymph of many chelicerate, crustacean, myriapod, and also possibly some insect species. The arthropod hemocyanins belong to a large protein superfamily that also includes the arthropod phenoloxidases, certain crustacean and insect storage proteins (pseudo-hemocyanins and hexamerins), and the insect hexamerin receptors. Here I summarise the present knowledge of the origin, functional adaptations, and evolution of these proteins. Arthropod and mollusc hemocyanins are, if at all, only distantly related. As early as in the arthropod stem line, the hemocyanins emerged from a phenoloxid…

In Search of Pathogens: Transcriptome-Based Identification of Viral Sequences from the Pine Processionary Moth (Thaumetopoea pityocampa)

2015

Thaumetopoea pityocampa (pine processionary moth) is one of the most important pine pests in the forests of Mediterranean countries, Central Europe, the Middle East and North Africa. Apart from causing significant damage to pinewoods, T. pityocampa occurrence is also an issue for public and animal health, as it is responsible for dermatological reactions in humans and animals by contact with its irritating hairs. High throughput sequencing technologies have allowed the fast and cost-effective generation of genetic information of interest to understand different biological aspects of non-model organisms as well as the identification of potential pathogens. Using these technologies, we have o…

Pituitary Function and the Somatotrophic System in Patients with Idiopathic Parkinson’s Disease Under Chronic Dopaminergic Therapy

2007

Idiopathic Parkinson's disease and dopaminergic medication may influence pituitary hormone secretion. The present study aimed to reveal any abnormalities of the somatotrophic system induced by the disease itself and/or the dopaminergic therapy. Investigations of other pituitary hormones under basal and stimulated conditions, as well as an analysis of body composition, were also performed. This was a controlled diagnostic study in which luteinising hormone-releasing hormone, thyroid-releasing hormone, corticotrophin-releasing hormone and arginine hydrochloride were administered to ten patients with idiopathic Parkinson's disease under dopaminergic medication. Basal and stimulated hormone con…

Phylogeny of Polycnemoideae (Amaranthaceae): Implications for biogeography, character evolution and taxonomy

2013

Conflicting molecular phylogenies of European long-eared bats (Plecotus) can be explained by cryptic diversity

2002

Abstract Conflicting phylogenetic signals of two data sets that analyse different portions of the same molecule are unexpected and require an explanation. In the present paper we test whether (i) differential evolution of two mitochondrial genes or (ii) cryptic diversity can better explain conflicting results of two recently published molecular phylogenies on the same set of species of long-eared bats (genus Plecotus). We sequenced 1714 bp of three mitochondrial regions (16S, ND1, and D-loop) of 35 Plecotus populations from 10 European countries. A likelihood ratio test revealed congruent phylogenetic signals of the three data partitions. Our phylogenetic analyses demonstrated that the exis…

Population structure and reticulate evolution of Saccharomyces eubayanus and its lager-brewing hybrids

2014

Reticulate evolution can be a major driver of diversification into new niches, especially in disturbed habitats and at the edges of ranges. Industrial fermentation strains of yeast provide a window into these processes, but progress has been hampered by a limited understanding of the natural diversity and distribution of Saccharomyces species and populations. For example, lager beer is brewed with Saccharomyces pastorianus, an alloploid hybrid of S. cerevisiae and S. eubayanus, a species only recently discovered in Patagonia, Argentina. Here, we report that genetically diverse strains of S. eubayanus are readily isolated from Patagonia, demonstrating that the species is well established the…

The population genetics and evolutionary epidemiology of RNA viruses.

2004

Key Points The authors discuss the main mechanisms of RNA virus evolution — mutation, recombination, natural selection, genetic drift and migration, and how these interact to shape the genetic structure of populations.The quasispecies model of RNA virus evolution is explained and the question of whether this model provides an accurate description of RNA virus evolution is discussed.Experiments that can be carried out to test the basic principles of evolutionary theory are briefly described. The authors review what such experiments have told us about virus evolution and, more widely, what these experiments have revealed in terms of general evolutionary principles.RNA viruses evolve quickly, …

Aslian linguistic prehistory: A case study in computational phylogenetics

2011

This paper analyzes newly collected lexical data from 26 languages of the Aslian subgroup of the Austroasiatic language family using computational phylogenetic methods. We show the most likely topology of the Aslian family tree, discuss rooting and external relationships to other Austroasiatic languages, and investigate differences in the rates of diversification of different branches. Evidence is given supporting the classification of Jah Hut as a fourth top level subgroup of the family. The phylogenetic positions of known geographic and linguistic outlier languages are clarified, and the relationships of the little studied Aslian languages of Southern Thailand to the rest of the family ar…

Phylogenetic relationship among genera of Polymorphidae (Acanthocephala), inferred from nuclear and mitochondrial gene sequences.

2013

Abstract Acanthocephalans of the family Polymorphidae Meyer, 1931 are obligate endoparasites with complex life cycles. These worms use vertebrates (marine mammals, fish-eating birds and waterfowl) as definitive hosts and invertebrates (amphipods, decapods and euphausiids) as intermediate hosts to complete their life cycle. Polymorphidae has a wordwide distribution, containing 12 genera, with approximately 127 species. The family is diagnosed by having a spinose trunk, bulbose proboscis, double-walled proboscis receptacle, and usually four to eight tubular cement glands. To conduct a phylogenetic analysis, in the current study sequences of the small (18S) and large-subunit (28S) ribosomal RN…