morphological evolution
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A high degree of morphological variability is expressed between the ornately sculptured siliceous scales formed by species in the chrysophycean genus, Synura. In this study, we aimed to uncover the general principles and trends underlying the evolution of scale morphology in this genus. We assessed the relationships among thirty extant Synura species using a robust molecular analysis that included six genes, coupled with morphological characterization of the species-specific scales. The analysis was further enriched with addition of morphological information from fossil specimens and by including the unique modern species, Synura punctulosa. We inferred the phylogenetic position of the morphologically unique S. punctulosa, to be an ancient Synura lineage related to S. splendida in the section Curtispinae. Some morphological traits, including development of a keel or a labyrinth ribbing pattern on the scale, appeared once in evolution, whereas other structures, such as a hexagonal meshwork pattern, originated independently several times over geologic time. We further uncovered numerous construction principles governing scale morphology and evolution, as follows: (i) scale roundness and pore diameter decreased during evolution; (ii) elongated scales became strengthened by a higher number of struts or ribs; (iii) as a consequence of scale biogenesis, scales with spines possessed smaller basal holes than scales with a keel and; and (iv) the keel area was proportional to scale area, indicating its potential value in strengthening the scale against breakage.
... The Structure of Adaptive Landscapes Underlying Protein Evolution, 121 -- Adaptive Maturation of the ... ... Immune Response, 122 Evolution of Novel Catalytic Functions, 142 -- Applied Molecular Evolution: Direct ... ... - PART III ORDER AND ONTOGENY, 407 -- 11 The Architecture of Genetic Regulatory Circuits and Its Evolution ... ... , 411 -- Independence of the Molecular Evolutionary Clock and Morphological Evolution, 412 -- CONTENTS ... ... Morphology, Maps, and the Spatial Ordering of Integrated Tissues, 537 -- Induction as a Basic Intercellular ...
1st ed. 709 s. : il.
- Klíčová slova
- Biologie, Evoluce, Fylogeneze,
- MeSH
- biologická evoluce MeSH
- biologie MeSH
- fylogeneze MeSH
- molekulární evoluce MeSH
- původ života MeSH
The evolution of phenotypes is highly understudied in protists, due to the dearth of morphological characters, missing fossil record, and/or unresolved phylogeny in the majority of taxa. The chrysophyte genus Mallomonas (Stramenopiles) forms species-specific silica scales with extraordinary diversity of their ornamentation. In this paper, we molecularly characterized three additional species to provide an updated phylogeny of 43 species, and combined this with evaluations of 24 morphological traits. Using phylogenetic comparative methods, we evaluated phylogenetic signal in traits, reconstructed the trait evolution, and compared the overall phylogenetic and morphological diversity. The majority of traits showed strong phylogenetic signal and mostly dynamic evolution. Phylogenetic relatedness was often reflected by the phenotypic similarity. Both V-rib and dome are very conservative structures that are presumably involved in precise scale overlap and bristle attachment, respectively. Based on modern species, it seems the dome firstly appeared on apical and/or caudal scales, and only later emerged on body scales. Bristle was presumably present in the common ancestor and gradually elongated ever since. However, most other morphological traits readily changed during the evolution of Mallomonas.
Micrasterias, the name of which is derived from the Greek for 'little star', comprises possibly the most spectacularly shaped desmids (Desmidiales, Streptophyta). Presently, the genus Micrasterias includes about 60 traditional species, the majority of which were described in the early 19th century. We used a comprehensive multigene dataset (including SSU rDNA, psaA, and coxIII loci) of 34 Micrasterias taxa to assess the relationships between individual morphological species. The resulting phylogeny was used to assess the patterns characterizing the morphological evolution of this genus. The phylogenetic analysis led to the recognition of eight well-resolved lineages that could be characterized by selected morphological features. Apart from the members of Micrasterias, three species belonged to different traditional desmid genera (Cosmarium, Staurodesmus, and Triploceras) and were inferred to be nested within the genus. Morphological comparisons of these species with their relatives revealed an accelerated rate of morphological evolution. Mapping morphological diversification of the genus on the phylogenetic tree revealed profound differences in the phylogenetic signal of selected phenotypic features. Whereas the branching pattern of the cells clearly correlated with the phylogeny, cell complexity possibly reflected rather their adaptive morphological responses to environmental conditions. Finally, ancestral reconstruction of distribution patterns indicated potential origin of the genus in North America, with additional speciation events occurring in the Indo-Malaysian region.
- MeSH
- Bayesova věta MeSH
- databáze genetické MeSH
- fylogeneze MeSH
- fylogeografie MeSH
- genetické lokusy genetika MeSH
- malé podjednotky ribozomu genetika MeSH
- Micrasterias anatomie a histologie genetika MeSH
- modely genetické MeSH
- ribozomální DNA genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Despite their long history with the basal split dating back to the Eocene, all species of monitor lizards (family Varanidae) studied so far share the same chromosome number of 2n = 40. However, there are differences in the morphology of the macrochromosome pairs 5-8. Further, sex determination, which revealed ZZ/ZW sex microchromosomes, was studied only in a few varanid species and only with techniques that did not test their homology. The aim of this study was to (i) test if cryptic interchromosomal rearrangements of larger chromosomal blocks occurred during the karyotype evolution of this group, (ii) contribute to the reconstruction of the varanid ancestral karyotype, and (iii) test homology of sex chromosomes among varanids. We investigated these issues by hybridizing flow sorted chromosome paints from Varanus komodoensis to metaphases of nine species of monitor lizards. The results show that differences in the morphology of the chromosome pairs 5-8 can be attributed to intrachromosomal rearrangements, which led to transitions between acrocentric and metacentric chromosomes in both directions. We also documented the first case of spontaneous triploidy among varanids in Varanus albigularis. The triploid individual was fully grown, which demonstrates that polyploidization is compatible with life in this lineage. We found that the W chromosome differs between species in size and heterochromatin content. The varanid Z chromosome is clearly conserved in all the analyzed species. Varanids, in addition to iguanas, caenophidian snakes, and lacertid lizards, are another squamate group with highly conserved sex chromosomes over a long evolutionary time.
- MeSH
- heterochromatin genetika MeSH
- ještěři genetika MeSH
- karyotyp MeSH
- karyotypizace metody MeSH
- molekulární evoluce MeSH
- pohlavní chromozomy genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Rose chafers (Cetoniinae) are a large group of flower visitors within the pleurostict Scarabaeidae that are characterized by their distinctive flight mode with nearly closed forewings. Despite their popularity, this is the first study to use molecular data to infer their phylogenetic relationships. We used partial gene sequences for 28S rRNA, cytochrome oxidase I (cox1) and 16S rRNA (rrnL) for 299 species, representing most recognized subfamilies of Scarabaeidae, including 125 species of Cetoniinae. Combined analyses using maximum parsimony, maximum likelihood and Bayesian inferences recovered Cetoniinae as monophyletic in all analyses, with the sister clade composed of Rutelinae and Dynastinae. Rutelinae was always recovered as paraphyletic with respect to Dynastinae. Trichiini sensu lato (s.l.) was recovered as a polyphyletic clade, while Cetoniini s.l. was recovered as paraphyletic. The inferred topologies were also supported by site bootstrapping of the ML trees. With the exception of Cremastochelini, most tribes of Cetoniinae were poly- or paraphyletic, indicating the critical need for a careful revision of rose chafer classification. Analysis of elytral base structure (including 11 scored characters) in the context of phylogeny, revealed a complex, concerted and rapid transformation of the single trait elements linked to a modified flight mode with closed elytra. This appears to be unlinked to the lateral sinuation of the elytra, which originated independently several times at later stages in the evolution of the group.
- MeSH
- Bayesova věta MeSH
- biologická evoluce * MeSH
- brouci klasifikace genetika MeSH
- DNA chemie izolace a purifikace metabolismus MeSH
- fylogeneze MeSH
- křídla zvířecí anatomie a histologie MeSH
- respirační komplex IV genetika MeSH
- RNA ribozomální 16S genetika MeSH
- RNA ribozomální 28S genetika MeSH
- sekvenční analýza DNA MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Angiosperms have become the dominant terrestrial plant group by diversifying for ~145 million years into a broad range of environments. During the course of evolution, numerous morphological innovations arose, often preceded by whole genome duplications (WGD). The mustard family (Brassicaceae), a successful angiosperm clade with ~4000 species, has been diversifying into many evolutionary lineages for more than 30 million years. Here we develop a species inventory, analyze morphological variation, and present a maternal, plastome-based genus-level phylogeny. We show that increased morphological disparity, despite an apparent absence of clade-specific morphological innovations, is found in tribes with WGDs or diversification rate shifts. Both are important processes in Brassicaceae, resulting in an overall high net diversification rate. Character states show frequent and independent gain and loss, and form varying combinations. Therefore, Brassicaceae pave the way to concepts of phylogenetic genome-wide association studies to analyze the evolution of morphological form and function.
The archamoebae form a small clade of anaerobic/microaerophilic flagellates or amoebae, comprising the pelobionts (mastigamoebids and pelomyxids) and the entamoebae. It is a member of the eukaryotic supergroup Amoebozoa. We examined 22 strains of 13 species of Mastigamoeba, Pelomyxa and Rhizomastix by light-microscopy and determined their SSU rRNA gene sequences. The SSU rRNA gene sequences of Pelomyxa palustris and Mastigella commutans in GenBank are shown to belong to P. stagnalis and Mastigamoeba punctachora, respectively. Five new species of free-living archamoebae are described: Mastigamoeba abducta, M. errans, M. guttula, M. lenta, and Rhizomastix libera spp. nov. A species of Mastigamoeba possibly living endosymbiotically in Pelomyxa was identified. Rhizomastix libera, the first known free-living member of that genus, is shown to be an archamoeba. R. libera possesses an ultrastructure unique within archamoebae: a rhizostyle formed from a modified microtubular cone and a flagellum with vanes. While many nominal species of pelobionts are extremely hard to distinguish by light microscopy, transient pseudopodial characters are worthy of further investigation as taxonomic markers.
- MeSH
- Archamoebae klasifikace genetika ultrastruktura MeSH
- druhová specificita MeSH
- Endolimax klasifikace genetika ultrastruktura MeSH
- Entamoeba klasifikace genetika ultrastruktura MeSH
- fylogeneze MeSH
- geny rRNA MeSH
- mikroskopie MeSH
- molekulární evoluce * MeSH
- protozoální DNA analýza MeSH
- sekvenční analýza DNA MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
