74 research outputs found

    Diversity, Phylogeny and Expression Patterns of Pou and Six Homeodomain Transcription Factors in Hydrozoan Jellyfish Craspedacusta sowerbyi

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    Formation of all metazoan bodies is controlled by a group of selector genes including homeobox genes, highly conserved across the entire animal kingdom. The homeobox genes from Pou and Six classes are key members of the regulation cascades determining development of sensory organs, nervous system, gonads and muscles. Besides using common bilaterian models, more attention has recently been targeted at the identification and characterization of these genes within the basal metazoan phyla. Cnidaria as a diploblastic sister group to bilateria with simple and yet specialized organs are suitable models for studies on the sensory organ origin and the associated role of homeobox genes. In this work, Pou and Six homeobox genes, together with a broad range of other sensory-specific transcription factors, were identified in the transcriptome of hydrozoan jellyfish Craspedacusta sowerbyi. Phylogenetic analyses of Pou and Six proteins revealed cnidarian-specific sequence motifs and contributed to the classification of individual factors. The majority of the Craspedacusta sowerbyi Pou and Six homeobox genes are predominantly expressed in statocysts, manubrium and nerve ring, the tissues with sensory and nervous activities. The described diversity and expression patterns of Pou and Six factors in hydrozoan jellyfish highlight their evolutionarily conserved functions. This study extends the knowledge of the cnidarian genome complexity and shows that the transcriptome of hydrozoan jellyfish is generally rich in homeodomain transcription factors employed in the regulation of sensory and nervous functions

    Morphological variations of three-rooted mandibular molars in ancient anatolian populations (Dilkaya Mound, Van, Turkey): A literature review on world populations

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    This study reports the first recorded discovery of three-rooted mandibular molars (3RM) from a Middle Age archaeological population unearthed in Van, Eastern Anatolia. A historical context is given for the research site, Dilkaya Mound, which has a history of approximately 2500 years. In total 462 permanent first and second teeth, 219 deciduous teeth, and a total of 682 mandibular teeth belonging to 358 individuals from Early Iron Age and Middle Age populations were included in this study. The earliest recorded population on site which dates to the Early Iron Age shows no sign of 3RM1 and 3RM2. The 3RM1 feature first appears in Anatolia at a rate of 1,05% by the Middle Age. The frequency of 3RM2 was found at a rate of 0,67%, and 3RM3 at a rate of 2,44 % in the population. Three rooted deciduous lower first molar teeth (3rm1) were observed at a rate of 2,44%; a new feature in the literature. The results of our study support the existing explanation that genetic drift plays a significant role in the distribution of 3RM via the wave of migration to the west from Asia during the Middle Age. © 2014 MAA Printed in Greece. All rights reserved
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