| 1. |
- Praher, D., et al.
(författare)
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Conservation and turnover of miRNAs and their highly complementary targets in early branching animals
- 2021
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Ingår i: Proceedings of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 288:1945
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Tidskriftsartikel (refereegranskat)abstract
- MicroRNAs (miRNAs) are crucial post-transcriptional regulators that have been extensively studied in Bilateria, a group comprising the majority of extant animals, where more than 30 conserved miRNA families have been identified. By contrast, bilaterian miRNA targets are largely not conserved. Cnidaria is the sister group to Bilateria and thus provides a unique opportunity for comparative studies. Strikingly, like their plant counterparts, cnidarian miRNAs have been shown to predominantly have highly complementary targets leading to transcript cleavage by Argonaute proteins. Here, we assess the conservation of miRNAs and their targets by small RNA sequencing followed by miRNA target prediction in eight species of Anthozoa (sea anemones and corals), the earliest-branching cnidarian class. We uncover dozens of novel miRNAs but only a few conserved ones. Further, given their high complementarity, we were able to computationally identify miRNA targets in each species. Besides evidence for conservation of specific miRNA target sites, which are maintained between sea anemones and stony corals across 500 Myr of evolution, we also find indications for convergent evolution of target regulation by different miRNAs. Our data indicate that cnidarians have only few conserved miRNAs and corresponding targets, despite their high complementarity, suggesting a high evolutionary turnover.
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| 2. |
- Dnyansagar, R., et al.
(författare)
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Dispersal and speciation: The cross Atlantic relationship of two parasitic cnidarians
- 2018
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903. ; 126, s. 346-355
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Tidskriftsartikel (refereegranskat)abstract
- How dispersal strategies impact the distribution of species and subsequent speciation events is a fundamental question in evolutionary biology. Sedentary benthic marine organisms, such as corals or sea anemones usually rely on motile larval stages for dispersal and therefore have a relatively restricted distribution along coasts. Edwardsiella lineata and Edwardsiella carnea are virtually indistinguishable edwardsiid sea anemones native to the east American and the Northern European coast, respectively. E. lineata is a facultative parasite to the ctenophore Mnemiopsis leidyi, while the life cycle of E. carnea is unknown. Recently M. leidyi was found in the Skagerrak carrying Edwardsiella sp. parasites, which raised the intriguing possibility that the invasive comb jellies acted as cargo for the facultative E. lineata parasites to establish a new population in Northern Europe. Here, we assessed the genetic differences between these two cryptic Edwardsiella species and isolated parasites from the invasive comb jelly M. leidyi in Sweden by comparing rRNA, whole transcriptomes, SNPs, ITS2 sequences and the gene complements of key developmental regulators, the Wnt gene family. We show that E. carnea and the parasite transcriptomes are more than 99% identical, hence demonstrating that E. carnea has a previously unknown parasitic life stage. ITS2 sequence analysis of E. carnea and E. lineata suggest that they may not be reproductively isolated. The transcriptomes of E. lineata and E. carnea are similar to 97% identical. We also estimate that the species diverged between 18.7 and 21.6 million years ago.
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