@article{DedukhDaCruzKneitzetal.2022, author = {Dedukh, Dmitrij and Da Cruz, Irene and Kneitz, Susanne and Marta, Anatolie and Ormanns, Jenny and Tichop{\´a}d, Tom{\´a}š and Lu, Yuan and Alsheimer, Manfred and Janko, Karel and Schartl, Manfred}, title = {Achiasmatic meiosis in the unisexual Amazon molly, Poecilia formosa}, series = {Chromosome Research}, volume = {30}, journal = {Chromosome Research}, number = {4}, doi = {10.1007/s10577-022-09708-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325128}, pages = {443-457}, year = {2022}, abstract = {Unisexual reproduction, which generates clonal offspring, is an alternative strategy to sexual breeding and occurs even in vertebrates. A wide range of non-sexual reproductive modes have been described, and one of the least understood questions is how such pathways emerged and how they mechanistically proceed. The Amazon molly, Poecilia formosa, needs sperm from males of related species to trigger the parthenogenetic development of diploid eggs. However, the mechanism, of how the unreduced female gametes are produced, remains unclear. Cytological analyses revealed that the chromosomes of primary oocytes initiate pachytene but do not proceed to bivalent formation and meiotic crossovers. Comparing ovary transcriptomes of P. formosa and its sexual parental species revealed expression levels of meiosis-specific genes deviating from P. mexicana but not from P. latipinna. Furthermore, several meiosis genes show biased expression towards one of the two alleles from the parental genomes. We infer from our data that in the Amazon molly diploid oocytes are generated by apomixis due to a failure in the synapsis of homologous chromosomes. The fact that this failure is not reflected in the differential expression of known meiosis genes suggests the underlying molecular mechanism may be dysregulation on the protein level or misexpression of a so far unknown meiosis gene, and/or hybrid dysgenesis because of compromised interaction of proteins from diverged genomes.}, language = {en} } @article{LiuChenGaoetal.2017, author = {Liu, Han and Chen, Chunhai and Gao, Zexia and Min, Jiumeng and Gu, Yongming and Jian, Jianbo and Jiang, Xiewu and Cai, Huimin and Ebersberger, Ingo and Xu, Meng and Zhang, Xinhui and Chen, Jianwei and Luo, Wei and Chen, Boxiang and Chen, Junhui and Liu, Hong and Li, Jiang and Lai, Ruifang and Bai, Mingzhou and Wei, Jin and Yi, Shaokui and Wang, Huanling and Cao, Xiaojuan and Zhou, Xiaoyun and Zhao, Yuhua and Wei, Kaijian and Yang, Ruibin and Liu, Bingnan and Zhao, Shancen and Fang, Xiaodong and Schartl, Manfred and Qian, Xueqiao and Wang, Weimin}, title = {The draft genome of blunt snout bream (Megalobrama amblycephala) reveals the development of intermuscular bone and adaptation to herbivorous diet}, series = {GigaScience}, volume = {6}, journal = {GigaScience}, number = {7}, doi = {10.1093/gigascience/gix039}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170844}, year = {2017}, abstract = {The blunt snout bream Megalobrama amblycephala is the economically most important cyprinid fish species. As an herbivore, it can be grown by eco-friendly and resource-conserving aquaculture. However, the large number of intermuscular bones in the trunk musculature is adverse to fish meat processing and consumption. As a first towards optimizing this aquatic livestock, we present a 1.116-Gb draft genome of M. amblycephala, with 779.54 Mb anchored on 24 linkage groups. Integrating spatiotemporal transcriptome analyses, we show that intermuscular bone is formed in the more basal teleosts by intramembranous ossification and may be involved in muscle contractibility and coordinating cellular events. Comparative analysis revealed that olfactory receptor genes, especially of the beta type, underwent an extensive expansion in herbivorous cyprinids, whereas the gene for the umami receptor T1R1 was specifically lost in M. amblycephala. The composition of gut microflora, which contributes to the herbivorous adaptation of M. amblycephala, was found to be similar to that of other herbivores. As a valuable resource for the improvement of M. amblycephala livestock, the draft genome sequence offers new insights into the development of intermuscular bone and herbivorous adaptation.}, language = {en} } @article{BiscottiGerdolCanapaetal.2016, author = {Biscotti, Maria Assunta and Gerdol, Marco and Canapa, Adriana and Forconi, Mariko and Olmo, Ettore and Pallavicini, Alberto and Barucca, Marco and Schartl, Manfred}, title = {The Lungfish Transcriptome: A Glimpse into Molecular Evolution Events at the Transition from Water to Land}, series = {Scientific Reports}, volume = {6}, journal = {Scientific Reports}, number = {21571}, doi = {10.1038/srep21571}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167753}, year = {2016}, abstract = {Lungfish and coelacanths are the only living sarcopterygian fish. The phylogenetic relationship of lungfish to the last common ancestor of tetrapods and their close morphological similarity to their fossil ancestors make this species uniquely interesting. However their genome size, the largest among vertebrates, is hampering the generation of a whole genome sequence. To provide a partial solution to the problem, a high-coverage lungfish reference transcriptome was generated and assembled. The present findings indicate that lungfish, not coelacanths, are the closest relatives to land-adapted vertebrates. Whereas protein-coding genes evolve at a very slow rate, possibly reflecting a "living fossil" status, transposable elements appear to be active and show high diversity, suggesting a role for them in the remarkable expansion of the lungfish genome. Analyses of single genes and gene families documented changes connected to the water to land transition and demonstrated the value of the lungfish reference transcriptome for comparative studies of vertebrate evolution.}, language = {en} }