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Mosaic Distribution (mosaic + distribution)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

A stem lineage representative of buttonquails from the Lower Oligocene of Germany , fossil evidence for a charadriiform origin of the Turnicidae

IBIS, Issue 4 2007
GERALD MAYR
A new species of the charadriiform taxon Turnipax Mayr, 2000 is described from the Lower Oligocene fossil site Frauenweiler in southern Germany. The postcranial skeleton assigned to Turnipax oechslerorum sp. nov. is very well preserved and allows the recognition of significant, previously unknown osteological details of Turnipax, especially concerning the wing and pectoral girdle bones. We provide evidence that Turnipax is a stem lineage representative of the Turnicidae (buttonquails) and synonymize Turnipacidae Mayr, 2000 with Turnicidae Gray, 1840. Turnipax is the earliest fossil representative of the Turnicidae, which otherwise have no Paleogene fossil record. Because recent molecular studies support a charadriiform origin of buttonquails, the mosaic distribution in the skeleton of Turnipax of derived features of the Turnicidae and non-turnicid charadriiform birds is of particular interest. Turnipax exhibits a more plesiomorphic morphology than extant Turnicidae, and we assume that its habitat and way of living differed from that of crown group Turnicidae, which may not have diversified before the spread of grasslands during the Oligocene and Miocene. [source]

MOLECULAR AND PHYLOGENETIC CHARACTERIZATION OF PHORMIDIUM SPECIES (CYANOPROKARYOTA) USING THE CPCB-IGS-CPCA LOCUS,

JOURNAL OF PHYCOLOGY, Issue 1 2005
Ivanka Teneva
The accurate determination of species of Cyanoprokaryota/Cyanophyceae has many important applications. These include the assessment of risk with regard to blooms in water reservoirs as well as the identification of species capable of producing valuable bioactive compounds. Commonly, Cyanoprokaryota are classified based on their morphology. However, morphological criteria are not always reliable because they may change, for example, due to environmental factors. Thus, genetic and molecular analyses are a promising additional approach, but their application has so far been limited to relatively few genera. In light of this, we present here the first characterization of species and strains of the genus Phormidium Kütz. based on the cpcB-IGS-cpcA locus of the phycocyanin operon. In phylogenetic analyses using deduced amino acid sequences of the cpcB-cpcA regions, Phormidium was found to be polyphyletic. This analysis appeared to be dominated by the cpcB region, which is characterized by a relatively high percentage of informative substitutions. The percentage of variable positions within the cpcB-IGS-cpcA locus overall was 16.5%, thereby indicating a level of divergence remarkably higher than that reported for Nodularia and Arthrospira in previous studies relying on cpcB-IGS-cpcA. Further, alignment of informative nucleotide substitutions in the cpcB-IGS-cpcA sequences revealed a mosaic distribution, which may be indicative of genetic recombination events. Finally, the length and sequences of the IGS region alone proved useful as markers to differentiate the cyanobacterial genus Phormidium. However, whether the IGS region per se is sufficiently discriminatory to differentiate between Phormidium species or even strains requires further investigation using newly identified Phormidium sequence data. [source]

Evolutionary history of vertebrate appendicular muscle

BIOESSAYS, Issue 5 2001
Frietson Galis
The evolutionary history of muscle development in the paired fins of teleost fish and the limbs of tetrapod vertebrates is still, to a large extent, uncertain. There has been a consensus, however, that in the vertebrate clade the ancestral mechanism of fin and limb muscle development involves the extension of epithelial tissues from the somite into the fin/limb bud. This mechanism has been documented in chondrichthyan, dipnoan, chondrostean and teleost fishes. It has also been assumed that in amniotes, in contrast, individual progenitor cells of muscles migrate from the somites into the limb buds. Neyt et al.(1) now present the exciting finding that in zebrafishes this presumably derived mechanism involving individual cell migration, is present. They conclude, based on data on sharks, zebrafishes, chickens, quails and mice that the derived mechanism was present in the sarcopterygians. This conclusion, however, may be premature in the light of further data available in the literature, which show a highly mosaic distribution of this character in the vertebrate clade. Furthermore, a developmental mode exists that is intermediate between the supposed ancestral and derived modes in teleosts, reptiles and possibly amphibians. BioEssays 23:383,387, 2001. © 2001 John Wiley & Sons, Inc. [source]

A boy born with multiple lesions of atrophoderma

ACTA PAEDIATRICA, Issue 3 2010
Piero Pavone
Abstract Aims:, The Atrophodermas include a large group of disorders appearing as localized or widespread depressed skin areas and characterized by underlying dermal atrophy. The present study aims to report a peculiar form of previously unreported focal dermal atrophy. Methods:, We studied over a period of 5 years a boy who manifested, since birth, multiple hypopigmented cutaneous atrophic lesions of the atrophoderma type in a mosaic distribution over the body and the legs. Results:, This boy did no develop other cutaneous or systemic stigmata except for an idiopathic thrombocytopenic purpura (ITP) manifested at age 2 years. Full serum, metabolic and infective analyses; full ophthalmological examination; ultrasound examination of the heart and internal organs; skeletal x-rays; brain magnetic resonance imaging; and DNA analysis of the PORCN (Focal Dermal Hypoplasia - FDH) gene in this boy yielded normal results. Pathological analysis of multiple skin specimens from an affected area revealed slightly reduced dermal thickness; hyperpigmentation of the basal layer; homogenized and disarrayed collagen bundles; perivascular chronic infiltrates of lymphocytes and histiocytes; and normal skin appendages. Currently, the child is healthy; he has mildly improved skin status with less-evident skin depression throughout the lesion areas and no further complication has been recorded. The histological and clinical appearance of the skin lesions and the course were against any known disorder in the group of the atrophodermas. Conclusions:, The cutaneous lesions seen in this boy represent a possibly new congenital skin disorder characterized by multiple, benign areas of focal dermal atrophy in a mosaic distribution. [source]