Search results for "phylogeny"
showing 10 items of 1398 documents
Chromosome painting of the pygmy tree shrew shows that no derived cytogenetic traits link primates and scandentia.
2012
We hybridized human chromosome paints on metaphases of the pygmy tree shrew (<i>Tupaia minor</i>, Scandentia). The lack of the ancestral mammalian 4/8 association in both Primates and Scandentia was long considered a cytogenetic landmark that phylogenetically linked these mammalian orders. However, our results show that the association 4/8 is present in <i>Tupaia </i>along with not previously reported associations for 1/18 and 7/10. Altogether there are 11 syntenic associations of human chromosome segments in the pygmy tree shrew karyotype: 1/18, 2/21, 3/21, 4/8, 7/10, 7/16, 11/20, 12/22 (twice), 14/15 and 16/19. Our data remove any cytogenetic evidence that Scandent…
Molecular phylogenetics of Melastomataceae and Memecylaceae: implications for character evolution
2001
Melastomataceae are among the most abundant and diversified groups of plants throughout the tropics, but their intrafamily relationships and morphological evolution are poorly understood. Here we report the results of parsimony and maximum likelihood (ML) analyses of cpDNA sequences from the rbcL and ndhF genes and the rpl16 intron, generated for eight outgroups (Crypteroniaceae, Alzateaceae, Rhynchocalycaceae, Oliniaceae, Penaeaceae, Myrtaceae, and Onagraceae) and 54 species of melastomes. The sample represents 42 of the family’s currently recognized ~150 genera, the 13 traditional tribes, and the three subfamilies, Astronioideae, Melastomatoideae, and Memecyloideae (= Memecylaceae DC.). P…
Effects of climate and land-use change on species abundance in a Central European bird community.
2007
Although it is known that changes in land use and climate have an impact on ecological communities, it is unclear which of these factors is currently most important. We sought to determine the influence of land-use and climate alteration on changes in the abundance of Central European birds. We examined the impact of these factors by contrasting abundance changes of birds of different breeding habitat, latitudinal distribution, and migratory behavior. We examined data from the semiquantitative Breeding Bird Atlas of Lake Constance, which borders Germany, Switzerland, and Austria. Changes in the regional abundance of the 159 coexisting bird species from 1980-1981 to 2000-2002 were influenced…
Positive selection in development and growth rate regulation genes involved in species divergence of the genus Radix
2015
AbstractBackgroundLife history traits like developmental time, age and size at maturity are directly related to fitness in all organisms and play a major role in adaptive evolution and speciation processes. Comparative genomic or transcriptomic approaches to identify positively selected genes involved in species divergence can help to generate hypotheses on the driving forces behind speciation. Here we use a bottom-up approach to investigate this hypothesis by comparative analysis of orthologous transcripts of four closely related EuropeanRadixspecies.ResultsSnails of the genusRadixoccupy species specific distribution ranges with distinct climatic niches, indicating a potential for natural …
Evolutionary analysis of G-proteins in early metazoans: Cloning of α- and β-subunits from the sponge Geodia cydonium1The sequences reported here have…
1998
G-protein-coupled (seven-transmembrane segment)-receptors represent a major group of metazoan receptors, involved in transduction of extracellular signals. The G-proteins, which are made up of Galpha/beta/gamma-subunits, link the receptors to the effector system(s). To analyze the phylogenetic relationships among the metazoan alpha-subunits of G-proteins, cDNAs of alpha-subunits were isolated from Geodia cydonium, a marine sponge belonging to the lowest metazoan phylum, Porifera. One encodes a putative isotype of a stimulator of the adenylyl cyclase (Galpha s), another one a putative inhibitor of the adenylyl cyclase (Galpha i/o) and the third one a putative activator of phospholipase C (Ga…
A reappraisal of the Pleurotus eryngii complex – New species and taxonomic combinations based on the application of a polyphasic approach, and an ide…
2014
The Pleurotus eryngii species-complex comprises choice edible mushrooms growing on roots and lower stem residues of Apiaceae (umbellifers) plants. Material deriving from extensive sampling was studied by mating compatibility, morphological and ecological criteria, and through analysis of ITS1-5.8S-ITS2 and IGS1 rRNA sequences. Results revealed that P. eryngii sensu stricto forms a diverse and widely distributed aggregate composed of varieties elaeoselini, eryngii, ferulae, thapsiae, and tingitanus. Pleurotus eryngii subsp. tuoliensis comb. nov. is a phylogenetically sister group to the former growing only on various Ferula species in Asia. The existence of Pleurotus nebrodensis outside of S…
La pluralità dei sistemi musicali e le origini della musica (parte II)
2022
Il testo tratta la nascita degli interessi scientifici verso le tradizioni musicali extraoccidentali grazie alla nuova disciplina denominata "musicologia comparata" e agli studi etno-antropologici di orientamento evoluzionista e diffusionista. In questo contesto di studio viene dato particolare rilievo alle ipotesi riguardanti le origini della musica, che vengono sinteticamente ripercorse e valutate. The text deals with the birth of scientific interests towards extra-western musical traditions thanks to the new discipline called "comparative musicology" and to ethno-anthropological studies of evolutionist and diffusionist orientation. In this context of study, particular importance is given…
Chromosomal stasis versus plasmid plasticity in aphid endosymbiont Buchnera aphidicola.
2005
The study of three genomes of the aphid endosymbiont Buchnera aphidicola has revealed an extraordinary stasis: conservation of gene order and genetic composition of the chromosome, while the chromosome size and number of genes has reduced. The reduction in genome size appears to be ongoing since some lineages we now know to have even smaller chromosomes than the first B. aphidicola analysed. The current sequencing by our group of one of these smaller genomes with an estimated size of 450 kb, and its comparison with the other three available genomes provide insights into the nature of processes involved in shrinkage. We discuss whether B. aphidicola might be driven to extinction and be repla…
PVAmpliconFinder: a workflow for the identification of human papillomaviruses from high-throughput amplicon sequencing
2019
Abstract Background The detection of known human papillomaviruses (PVs) from targeted wet-lab approaches has traditionally used PCR-based methods coupled with Sanger sequencing. With the introduction of next-generation sequencing (NGS), these approaches can be revisited to integrate the sequencing power of NGS. Although computational tools have been developed for metagenomic approaches to search for known or novel viruses in NGS data, no appropriate tool is available for the classification and identification of novel viral sequences from data produced by amplicon-based methods. Results We have developed PVAmpliconFinder, a data analysis workflow designed to rapidly identify and classify kno…
Patterns of genetic and phenotypic variation in Iris haynei and I. atrofusca (Iris sect. Oncocyclus = the royal irises) along an ecogeographical grad…
2002
Iris haynei and I. atrofusca are two closely related narrow endemics distributed vicariously along an ecogeographical north-south gradient in Israel and the West Bank. To obtain baseline information of the taxonomic status, conservation and population history of these taxa, we investigated patterns of phenotypic variation and the partitioning of genetic variation within and among populations using dominant random amplified polymorphic DNA (RAPD) markers. Multivariate (principal components analysis) and taxonomic distance analyses based on morphometric traits from eight populations revealed no unambiguous separation into two distinct groups. Results of genetic analyses for nine populations d…