Search results for "Phylogenetics"

Phylogeny and evolution of the Arctium-Cousinia complex (Compositae, Cardueae-Carduinae)

2009

The phylogeny and evolution of the Arctium-Cousinia complex, including Arctium, Cousinia as one of the largest genera of Asteraceae, Hypacanthium and Schmalhausenia, is investigated. This group of genera has its highest diversity in the Irano-Turanian region and the mountains of Central Asia. We generated ITS and rpS4-trnT-trnL sequences for altogether 138 species, including 129 (of ca. 600) species of Cousinia. As found in previous analyses, Cousinia is not monophyletic. Instead, Cousinia subgg. Cynaroides and Hypacanthodes with together ca. 30 species are more closely related to Arctium, Hypacanthium and Schmalhausenia (Arctioid clade) than to subg. Cousinia (Cousinioid clade). The Arctio…

Morphological evolution and ecological diversification of the forest-dwelling poppies (Papaveraceae: Chelidonioideae) as deduced from a molecular phy…

1999

Sequences of the ITS region of nrDNA were analyzed for the seven genera of Papaveraceae subf. Chelidonioideae s.str. Three major clades can be recognized. These are 1.Chelidonium/Hylomecon/Stylophorum, 2.Eomecon/Sanguinaria, and 3.Bocconia/Macleaya. The monophyly of genera in the first of these three clades is doubtful, and clades two and three are sister to each other. Use of the ITS phylogeny of the subfamily to trace its morphological and ecological evolution shows that morphological change is concentrated in theBocconia/Macleaya clade, and probably related to the evolution of wind-pollination from insect-pollination in these two genera after habitat shift.

Molecular Phylogeny of Eumetazoa: Genes in Sponges (Porifera) Give Evidence for Monophyly of Animals

1998

At present, the universal phylogenetic tree exhibits a tripartite division of the living world and includes Bacteria (“eubacterial”), Archaea (“archebacterial”), and Eucarya (“eukaryotic”) branches (Woese et al. 1991) with the Progenote as the common ancestor (Woese 1987). It is difficult to assess the timely appearance of the first living organism. Some first decipherable evidence of early life has apparently been identified in Swaziland (South Africa) and Pilbara Supergroup (Western Australia) sediments, and dates back 3550 to 3000 Ma (million years) ago; these are stromatolites (see Walter 1996), microfossils, and particulate organic matter (reviewed in Schopf 1994). Eucarya are roughly …

An ITS phylogeny of tribe Senecioneae (Asteraceae) and a new delimitation of Senecio L.

2007

Senecioneae is the largest tribe ofAsteraceae, comprised ofca. 150 genera and 3,000 species. Approximately one-third of its species are placed in Senecio, making it one of the largest genera of flowering plants. Despite considerable efforts to classify and understand the striking morphological diversity in Senecioneae, little is known about its intergeneric relationships. This lack ofphylogenetic understanding is predominantly caused by conflicting clues from morphological characters, the large size ofthe tribe, and the absence of a good delimitation of Senecio. Phylogenetic analyses of nrITS and plastid DNA sequence data were used to produce a hypothesis of evolutionary relationships in Se…

Zoology and Animal Ecology: Abstract book : 3 February 2022, Nature House University of Latvia, Riga, Latvia

2022

L’audition chez les primates : entre forme, fonction, écologie et comportement

2019

The order Primates is composed of species whose morphologies, life history traits and behaviors are very diversified. The oldest representatives are dated about 65 million years. Because of this diversity, studies have focused on understanding the relationships between different parameters. Among the morphological structures studied, the basicranium, in particular the characters of the ear, have very often been considered in a phylogenetic perspective. Since the development of new acquisition techniques such as micro-tomography (μCT), new data are available. Thus, the interest for the morphology of the inner and middle ear, hitherto difficult to access, is growing. The structures of the ear…

Redescription and phylogenetic analysis of the type species of the genus Panagrellus Thorne, 1938 (Rhabditida, Panagrolaimidae), P. pycnus Thorne, 19…

2021

Abstract The identity of Panagrellus pycnus, the type species of the genus Panagrellus, is discussed after studying specimens from a cultured population collected in Italy that fits the original material of the species. A new characterization is consequently provided as follows: body 0.93–1.32 mm long, lip region continuous with the adjoining body, stoma with gymnostom very reduced, pharynx with not swollen metacorpus, neck 161–203 µm long, excretory pore at level of the metacorpus, post-vulval uterine sac 99–162 µm long or 2.6–3.8 times as long as the body diameter divided in a short tubular proximal part and a long swollen distal part, vulva post-equatorial (V = 63–69), female tail conica…

Zoology and Animal Ecology: Abstract book : 25 January 2023, Nature House University of Latvia, Riga, Latvia

2023

The Zoology and Animal Ecology section of the conference covers a broad range of topics, ranging from the distribution of animal species and the different aspects of species' interactions with the environment to animal genetics and physiology, including behaviour, conservation and other topics where study objects are animals.

Functional adaptations in the craniofacial morphology of Malagasy primates: shape variations associated with gummivory in the family Cheirogaleidae.

2005

Summary The infraorder Lemuriformes is characterized by a high level of homoplasy that clouds the evolutionary signal. The analysis of the morphological disparity of the Malagasy primates' crania and mandibles demonstrates the high determinism of functional specializations and developmental constraints, regardless of the phylogeny. In the present work, the weight of functional constraints linked to diet — a putative source of homoplasy — is analyzed first at the level of the infraorder Lemuriformes as a whole, and secondly at the level of a single family, the Cheirogaleidae, chosen because it contains taxa with two different diets (omnivory and gummivory). Malagasy primates are characterize…

Reconstructing the ancestor of Mycobacterium leprae: The dynamics of gene loss and genome reduction

2007

We have reconstructed the gene content and order of the last common ancestor of the human pathogens Mycobacterium leprae and Mycobacterium tuberculosis. During the reductive evolution of M. leprae, 1537 of 2977 ancestral genes were lost, among which we found 177 previously unnoticed pseudogenes. We find evidence that a massive gene inactivation took place very recently in the M. leprae lineage, leading to the loss of hundreds of ancestral genes. A large proportion of their nucleotide content (∼89%) still remains in the genome, which allowed us to characterize and date them. The age of the pseudogenes was computed using a new methodology based on the rates and patterns of substitution in the…