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Morphological Identity (morphological + identity)
Selected AbstractsCharacterization of the Hox cluster from the mosquito Anopheles gambiae (Diptera: culicidae)EVOLUTION AND DEVELOPMENT, Issue 6 2000Thomas P. Powers SUMMARY The Hox genes have been found to encode transcription factors, which specify the morphological identity of structures along the anteroposterior axis of animals ranging from worms to mice. The canonical set of nine genes is organized in a cluster in the genome of several protostomes and deuterostomes. However, within insects, whereas the Hox genes are organized in a single cluster in the beetle Tribolium castaneum, they are split into two separate groups in the flies Drosophila melanogaster and Drosophila virilis. The significance of a split Hox cluster is unknown and has been observed in only one organism outside the Drosophila lineage: the nematode Caenorhabditis elegans. We have cloned a majority of the Hox genes from the mosquito Anopheles gambiae (Diptera: Culicidae) and compared their genomic organization with that of Tribolium and Drosophila to determine if a split Hox cluster is found in dipterans aside from the Drosophilidae. We find that the Hox genes in Anopheles, as in Tribolium, are organized in a single cluster that spans a genomic region of at least 700 kb. This finding suggests that, within the insect genome, the partition of the Hox cluster may have evolved exclusively within the Drosophila lineage. The genomic structures of the resident genes, however, appear to be largely conserved between A. gambiae and D. melanogaster. [source] Morphology and environment: geographic distribution, ecological disjunction, and morphological variation in Actinocephalus polyanthus (Bong.) Sano (Eriocaulaceae)FEDDES REPERTORIUM, Issue 7-8 2008M. Trovó Most Brazilian Eriocaulaceae have highly restricted geographic distributions. Actinocephalus polyanthus (Bong.) Sano is one of the few widely distributed species; furthermore this distribution includes an interesting ecological disjunction. Actinocephalus polyanthus occurs in montane areas from northern Minas Gerais to Paraná, as well as coastal sand dune habitats in Santa Catarina and Rio Grande do Sul. In attempt to investigate whether there is any correlation between the ecological disjunction and the patterns of morphology exhibited by this species, eight populations were sampled covering the geographic distribution and the ecological disjunction. We used multivariate statistical methods (UPGMA, PCA and DF) to describe the morphology, and to verify its correlation with its distribution and habitat. We conclude that sand dune populations are morphologically different from the montane populations. The main difference in these plants is the robustness. The sand dune plants are significantly smaller than the plants from montane areas. We also verified that these populations have a morphological identity. The occurrence of this species in such diverse environments may reflect the morphological diversity of the various populations of the species, and may be the primary cause of the difference in these populations. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Morphologie und Umgebung: geographische Verbreitung, ökologische Disjunktion und morphologische Variabilität bei Actinocephalus polyanthus (Bong.) Sano (Eriocaulaceae) Die meisten brasilianischen Eriocaulaceae haben nur eine eng begrenzte geographische Verbreitung. Actinocephalus polyanthus (Bong.) Sano ist eine der wenigen weit verbreiteten Arten. Diese Verbreitung zeigt eine interessante ökologische Disjunktion: Actinocephalus polyanthus tritt auf in den Gebirgsregionen vom nördlichen Minas Gerais bis Paraná und in den Küsten-Sanddünen in Santa Catarina und Rio Grande do Sul. Im Versuch, ob sich irgendeine Korrelation zwischen der ökologischen Disjunktion und der morphologischen Ausprägung bei dieser Art finden lässt, sammelten wir acht Populationen aus dem geographischen Verbreitungsgebiet und der ökologischen Disjunktion. Es wurden multivariate statistische Methoden (UPGMA, PCA und DF) eingesetzt um die Morphologie zu beschreiben und diese Korrelation zwischen Verbreitung und Habitat zu vergleichen. Wir konnten daraus schließen, dass die Populationen der Sanddünen sich von den montanen Populationen unterscheiden. Der Hauptunterschied liegt in der Robustheit der Pflanzen: die der Sanddünen sind deutlich kleiner als die aus den Bergregionen. Wir beobachteten auch, dass diese Populationen morphologisch identisch sind. Das Vorkommen dieser Art in so unterschiedlicher Umgebung widerspiegelt die morphologischen Unterschiede der verschiedenen Populationen der Art, und stellt vermutlich die Hauptursache für die Unterschiede zwischen den Populationen dar. [source] Characterisation of human soft palate muscles with respect to fibre types, myosins and capillary supplyJOURNAL OF ANATOMY, Issue 2 2000PER S. STÅL Four human soft palate muscles, and palatopharyngeus, the uvula, the levator and tensor veli palatini were examined using enzyme-histochemical, immunohistochemical and biochemical methods and compared with human limb and facial muscles. Our results showed that each palate muscle had a distinct morphological identity and that they generally shared more similarities with facial than limb muscles. The palatopharyngeus and uvula muscles contained 2 of the highest proportions of type II fibres ever reported for human muscles. In contrast, the levator and tensor veli palatini muscles contained predominantly type I fibres. A fetal myosin heavy chain isoform (MyHC), not usually found in normal adult limb muscles, was present in a small number of fibres in all palate muscles. The mean muscle fibre diameter was smaller than in limb muscles and the individual and intramuscular variability in diameter and shape was considerable. All palate muscles had a high capillary density and an unusually high mitochondrial enzyme activity in the type II fibres, in comparison with limb muscles. No ordinary muscle spindles were observed. The fibre type and MyHC composition indicate that the palatopharyngeus and uvula muscles are functionally involved in quick movements whereas the levator and tensor veli palatini muscles perform slower and more continuous contractions. The high aerobic capacity and the rich capillarisation suggest that the palate muscles are relatively fatigue resistant. Absence of ordinary muscle spindles indicates a special proprioceptive control system. The special morphology of the palate muscles may be partly related to the unique anatomy with only one skeletal insertion, a feature consistent with muscle work at low load and tension and which may influence the cytoarchitecture of these muscles. Other important factors determining the special morphological characteristics might be specific functional requirements, distinct embryological origin and phylogenetic factors. [source] INTER- AND INTRASPECIFIC VARIATION OF THE PSEUDO-NITZSCHIA DELICATISSIMA COMPLEX (BACILLARIOPHYCEAE) ILLUSTRATED BY RRNA PROBES, MORPHOLOGICAL DATA AND PHYLOGENETIC ANALYSES,JOURNAL OF PHYCOLOGY, Issue 2 2006Nina Lundholm A study of 25 cultures tentatively identified as Pseudo-nitzschia delicatissima (Cleve) Heiden, and originating from geographically widely distributed locations, showed both morphological and genetic variation among strains. Use of rRNA-targeted DNA probes on 17 different strains showed large variation in the hybridization patterns. Detailed morphological studies placed the isolates into three groups. The sample on which the neotype of P. delicatissima is based was also examined, and used to establish the morphological identity of P. delicatissima. Phylogenetic analyses of 16 strains, based on sequences of internal transcriber spacer 1 (ITS1), 5.8S and ITS2 of the nuclear-encoded rDNA, supported the morphological observations and the hybridization studies, and revealed large genetic variation among strains. A combination of the morphological and molecular findings resulted in the description of two new species, P. decipiens sp. nov. and P. dolorosa sp. nov. P. dolorosa has a mixture of one or two rows of poroids in the striae whereas P. delicatissima always has two rows. In addition, P. dolorosa has wider valves and a lower density of poroids. P. decipiens differs from P. delicatissima by a higher density of striae on the valve face as well as a higher density of poroids on the girdle bands. Among the strains referred to P. delicatissima, an epitype was selected. Large genetic variation was found among the P. delicatissima strains and a subdivision into two major clades represent cryptic species. [source] | ||||||||||