@article{BiscottiCarducciBaruccaetal.2020, author = {Biscotti, Maria Assunta and Carducci, Federica and Barucca, Marco and Gerdol, Marco and Pallavicini, Alberto and Schartl, Manfred and Canapa, Adriana and Contar Adolfi, Mateus}, title = {The transcriptome of the newt Cynops orientalis provides new insights into evolution and function of sexual gene networks in sarcopterygians}, series = {Scientific Reports}, volume = {10}, journal = {Scientific Reports}, doi = {10.1038/s41598-020-62408-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227326}, year = {2020}, abstract = {Amphibians evolved in the Devonian period about 400 Mya and represent a transition step in tetrapod evolution. Among amphibians, high-throughput sequencing data are very limited for Caudata, due to their largest genome sizes among terrestrial vertebrates. In this paper we present the transcriptome from the fire bellied newt Cynops orientalis. Data here presented display a high level of completeness, comparable to the fully sequenced genomes available from other amphibians. Moreover, this work focused on genes involved in gametogenesis and sexual development. Surprisingly, the gsdf gene was identified for the first time in a tetrapod species, so far known only from bony fish and basal sarcopterygians. Our analysis failed to isolate fgf24 and foxl3, supporting the possible loss of both genes in the common ancestor of Rhipidistians. In Cynops, the expression analysis of genes described to be sex-related in vertebrates singled out an expected functional role for some genes, while others displayed an unforeseen behavior, confirming the high variability of the sex-related pathway in vertebrates.}, language = {en} } @article{BiscottiAdolfiBaruccaetal.2018, author = {Biscotti, Maria Assunta and Adolfi, Mateus Contar and Barucca, Marco and Forconi, Mariko and Pallavicini, Alberto and Gerdol, Marco and Canapa, Adriana and Schartl, Manfred}, title = {A comparative view on sex differentiation and gametogenesis genes in lungfish and coelacanths}, series = {Genome Biology and Evolution}, volume = {10}, journal = {Genome Biology and Evolution}, number = {6}, doi = {10.1093/gbe/evy101}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176774}, pages = {1430-1444}, year = {2018}, abstract = {Gonadal sex differentiation and reproduction are the keys to the perpetuation of favorable gene combinations and positively selected traits. In vertebrates, several gonad development features that differentiate tetrapods and fishes are likely to be, at least in part, related to the water-to-land transition. The collection of information from basal sarcopterygians, coelacanths, and lungfishes, is crucial to improve our understanding of the molecular evolution of pathways involved in reproductive functions, since these organisms are generally regarded as "living fossils" and as the direct ancestors of tetrapods. Here, we report for the first time the characterization of >50 genes related to sex differentiation and gametogenesis in Latimeria menadoensis and Protopterus annectens. Although the expression profiles of most genes is consistent with the intermediate position of basal sarcopterygians between actinopterygian fish and tetrapods, their phylogenetic placement and presence/absence patterns often reveal a closer affinity to the tetrapod orthologs. On the other hand, particular genes, for example, the male gonad factor gsdf (Gonadal Soma-Derived Factor), provide examples of ancestral traits shared with actinopterygians, which disappeared in the tetrapod lineage.}, language = {en} } @article{KangSchartlWalteretal.2013, author = {Kang, Ji Hyoun and Schartl, Manfred and Walter, Ronald B. and Meyer, Axel}, title = {Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily}, series = {BMC Evolutionary Biology}, volume = {13}, journal = {BMC Evolutionary Biology}, number = {25}, issn = {1471-2148}, doi = {10.1186/1471-2148-13-25}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121853}, year = {2013}, abstract = {Background: Males in some species of the genus Xiphophorus, small freshwater fishes from Meso-America, have an extended caudal fin, or sword - hence their common name "swordtails". Longer swords are preferred by females from both sworded and - surprisingly also, non-sworded (platyfish) species that belong to the same genus. Swordtails have been studied widely as models in research on sexual selection. Specifically, the pre-existing bias hypothesis was interpreted to best explain the observed bias of females in presumed ancestral lineages of swordless species that show a preference for assumed derived males with swords over their conspecific swordless males. However, many of the phylogenetic relationships within this genus still remained unresolved. Here we construct a comprehensive molecular phylogeny of all 26 known Xiphophorus species, including the four recently described species (X. kallmani, X. mayae, X. mixei and X. monticolus). We use two mitochondrial and six new nuclear markers in an effort to increase the understanding of the evolutionary relationships among the species in this genus. Based on the phylogeny, the evolutionary history and character state evolution of the sword was reconstructed and found to have originated in the common ancestral lineage of the genus Xiphophorus and that it was lost again secondarily. Results: We estimated the evolutionary relationships among all known species of the genus Xiphophorus based on the largest set of DNA markers so far. The phylogeny indicates that one of the newly described swordtail species, Xiphophorus monticolus, is likely to have arisen through hybridization since it is placed with the southern platyfish in the mitochondrial phylogeny, but with the southern swordtails in the nuclear phylogeny. Such discordance between these two types of markers is a strong indication for a hybrid origin. Additionally, by using a maximum likelihood approach the possession of the sexually selected sword trait is shown to be the most likely ancestral state for the genus Xiphophorus. Further, we provide a well supported estimation of the phylogenetic relationships between the previously unresolved northern swordtail groups. Conclusions: This comprehensive molecular phylogeny of the entire genus Xiphophorus provides evidence that a second swordtail species, X. monticolus, arose through hybridization. Previously, we demonstrated that X. clemenciae, another southern swordtail species, arose via hybridization. These findings highlight the potential key role of hybridization in the evolution of this genus and suggest the need for further investigations into how hybridization contributes to speciation more generally.}, language = {en} } @article{TomaszkiewiczChalopinSchartletal.2014, author = {Tomaszkiewicz, Marta and Chalopin, Domitille and Schartl, Manfred and Galiana, Delphine and Volff, Jean-Nicolas}, title = {A multicopy Y-chromosomal SGNH hydrolase gene expressed in the testis of the platyfish has been captured and mobilized by a Helitron transposon}, series = {BMC Genetics}, volume = {15}, journal = {BMC Genetics}, number = {44}, doi = {10.1186/1471-2156-15-44}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116746}, year = {2014}, abstract = {Background: Teleost fish present a high diversity of sex determination systems, with possible frequent evolutionary turnover of sex chromosomes and sex-determining genes. In order to identify genes involved in male sex determination and differentiation in the platyfish Xiphophorus maculatus, bacterial artificial chromosome contigs from the sex-determining region differentiating the Y from the X chromosome have been assembled and analyzed. Results: A novel three-copy gene called teximY (for testis-expressed in Xiphophorus maculatus on the Y) was identified on the Y but not on the X chromosome. A highly related sequence called texim1, probably at the origin of the Y-linked genes, as well as three more divergent texim genes were detected in (pseudo) autosomal regions of the platyfish genome. Texim genes, for which no functional data are available so far in any organism, encode predicted esterases/lipases with a SGNH hydrolase domain. Texim proteins are related to proteins from very different origins, including proteins encoded by animal CR1 retrotransposons, animal platelet-activating factor acetylhydrolases (PAFah) and bacterial hydrolases. Texim gene distribution is patchy in animals. Texim sequences were detected in several fish species including killifish, medaka, pufferfish, sea bass, cod and gar, but not in zebrafish. Texim-like genes are also present in Oikopleura (urochordate), Amphioxus (cephalochordate) and sea urchin (echinoderm) but absent from mammals and other tetrapods. Interestingly, texim genes are associated with a Helitron transposon in different fish species but not in urochordates, cephalochordates and echinoderms, suggesting capture and mobilization of an ancestral texim gene in the bony fish lineage. RT-qPCR analyses showed that Y-linked teximY genes are preferentially expressed in testis, with expression at late stages of spermatogenesis (late spermatids and spermatozeugmata). Conclusions: These observations suggest either that TeximY proteins play a role in Helitron transposition in the male germ line in fish, or that texim genes are spermatogenesis genes mobilized and spread by transposable elements in fish genomes.}, language = {en} } @article{GarciaMatosShenetal.2014, author = {Garcia, Tzintzuni I. and Matos, Isa and Shen, Yingjia and Pabuwal, Vagmita and Coelho, Maria Manuela and Wakamatsu, Yuko and Schartl, Manfred and Walter, Ronald B.}, title = {Novel Method for Analysis of Allele Specific Expression in Triploid Oryzias latipes Reveals Consistent Pattern of Allele Exclusion}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {6}, issn = {1932-6203}, doi = {10.1371/journal.pone.0100250}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116000}, pages = {e100250}, year = {2014}, abstract = {Assessing allele-specific gene expression (ASE) on a large scale continues to be a technically challenging problem. Certain biological phenomena, such as X chromosome inactivation and parental imprinting, affect ASE most drastically by completely shutting down the expression of a whole set of alleles. Other more subtle effects on ASE are likely to be much more complex and dependent on the genetic environment and are perhaps more important to understand since they may be responsible for a significant amount of biological diversity. Tools to assess ASE in a diploid biological system are becoming more reliable. Non-diploid systems are, however, not uncommon. In humans full or partial polyploid states are regularly found in both healthy (meiotic cells, polynucleated cell types) and diseased tissues (trisomies, non-disjunction events, cancerous tissues). In this work we have studied ASE in the medaka fish model system. We have developed a method for determining ASE in polyploid organisms from RNAseq data and we have implemented this method in a software tool set. As a biological model system we have used nuclear transplantation to experimentally produce artificial triploid medaka composed of three different haplomes. We measured ASE in RNA isolated from the livers of two adult, triploid medaka fish that showed a high degree of similarity. The majority of genes examined (82\%) shared expression more or less evenly among the three alleles in both triploids. The rest of the genes (18\%) displayed a wide range of ASE levels. Interestingly the majority of genes (78\%) displayed generally consistent ASE levels in both triploid individuals. A large contingent of these genes had the same allele entirely suppressed in both triploids. When viewed in a chromosomal context, it is revealed that these genes are from large sections of 4 chromosomes and may be indicative of some broad scale suppression of gene expression.}, language = {en} }