TY - JOUR A1 - Hilgers, Leon A1 - Hartmann, Stefanie A1 - Hofreiter, Michael A1 - von Rintelen, Thomas T1 - Novel Genes, Ancient Genes, and Gene Co-Option Contributed o the Genetic Basis of the Radula, a Molluscan Innovation JF - Molecular biology and evolution N2 - The radula is the central foraging organ and apomorphy of the Mollusca. However, in contrast to other innovations, including the mollusk shell, genetic underpinnings of radula formation remain virtually unknown. Here, we present the first radula formative tissue transcriptome using the viviparous freshwater snail Tylomelania sarasinorum and compare it to foot tissue and the shell-building mantle of the same species. We combine differential expression, functional enrichment, and phylostratigraphic analyses to identify both specific and shared genetic underpinnings of the three tissues as well as their dominant functions and evolutionary origins. Gene expression of radula formative tissue is very distinct, but nevertheless more similar to mantle than to foot. Generally, the genetic bases of both radula and shell formation were shaped by novel orchestration of preexisting genes and continuous evolution of novel genes. A significantly increased proportion of radula-specific genes originated since the origin of stem-mollusks, indicating that novel genes were especially important for radula evolution. Genes with radula-specific expression in our study are frequently also expressed during the formation of other lophotrochozoan hard structures, like chaetae (hes1, arx), spicules (gbx), and shells of mollusks (gbx, heph) and brachiopods (heph), suggesting gene co-option for hard structure formation. Finally, a Lophotrochozoa-specific chitin synthase with a myosin motor domain (CS-MD), which is expressed during mollusk and brachiopod shell formation, had radula-specific expression in our study. CS-MD potentially facilitated the construction of complex chitinous structures and points at the potential of molecular novelties to promote the evolution of different morphological innovations. KW - chitin synthase KW - novelty KW - radula KW - RNAseq KW - shell KW - Tylomelania sarasinorum Y1 - 2018 U6 - https://doi.org/10.1093/molbev/msy052 SN - 0737-4038 SN - 1537-1719 VL - 35 IS - 7 SP - 1638 EP - 1652 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Stelbrink, Björn A1 - von Rintelen, Thomas A1 - Richter, Kirsten A1 - Finstermeier, Knut A1 - Frahnert, Sylke A1 - Cracraft, Joel A1 - Hofreiter, Michael T1 - Insights into the geographical origin and phylogeographical patterns of Paradisaea birds-of-paradise JF - Zoological journal of the Linnean Society N2 - Birds-of-paradise represent a textbook example for geographical speciation and sexual selection. Perhaps the most iconic genus is Paradisaea, which is restricted to New Guinea and a few surrounding islands. Although several species concepts have been applied in the past to disentangle the different entities within this genus, no attempt has been made so far to uncover phylogeographical patterns based on a genetic dataset that includes multiple individuals per species. Here, we applied amplicon sequencing for the mitochondrial fragment Cytb for a total of 69 museum specimens representing all seven Paradisaea species described and inferred both phylogenetic relationships and colonization pathways across the island. Our analyses show that the most recent common ancestor of the diverging lineages within Paradisaea probably originated in the Late Miocene in the eastern part of the Central Range and suggest that tectonic processes played a key role in shaping the diversification and distribution of species. All species were recovered as monophyletic, except for those within the apoda-minor-raggiana clade, which comprises the allopatric and parapatric species P. apoda, P. minor and P. raggiana. The comparatively young divergence times, together with possible instances of mitochondrial introgression and incomplete lineage sorting, suggest recent speciation in this clade. KW - amplicon sequencing KW - Cytb KW - historical DNA KW - molecular clock KW - molecular phylogeny KW - museomics KW - New Guinea KW - Paradisaeidae Y1 - 2022 U6 - https://doi.org/10.1093/zoolinnean/zlac010 SN - 0024-4082 SN - 1096-3642 VL - 196 IS - 4 SP - 1394 EP - 1407 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Hilgers, Leon A1 - Hartmann, Stefanie A1 - Pfaender, Jobst A1 - Lentge-Maass, Nora A1 - Marwoto, Ristiyanti M. A1 - von Rintelen, Thomas A1 - Hofreiter, Michael T1 - Evolutionary divergence and radula diversification in two ecomorphs from an adaptive radiation of freshwater snails JF - Genes N2 - (1) Background: Adaptive diversification of complex traits plays a pivotal role in the evolution of organismal diversity. In the freshwater snail genus Tylomelania, adaptive radiations were likely promoted by trophic specialization via diversification of their key foraging organ, the radula. (2) Methods: To investigate the molecular basis of radula diversification and its contribution to lineage divergence, we used tissue-specific transcriptomes of two sympatric Tylomelania sarasinorum ecomorphs. (3) Results: We show that ecomorphs are genetically divergent lineages with habitat-correlated abundances. Sequence divergence and the proportion of highly differentially expressed genes are significantly higher between radula transcriptomes compared to the mantle and foot. However, the same is not true when all differentially expressed genes or only non-synonymous SNPs are considered. Finally, putative homologs of some candidate genes for radula diversification (hh, arx, gbb) were also found to contribute to trophic specialization in cichlids and Darwin's finches. (4) Conclusions: Our results are in line with diversifying selection on the radula driving Tylomelania ecomorph divergence and indicate that some molecular pathways may be especially prone to adaptive diversification, even across phylogenetically distant animal groups. KW - speciation KW - adaptive radiation KW - molluscs KW - RNAseq KW - regulatory evolution KW - trophic specialization Y1 - 2022 U6 - https://doi.org/10.3390/genes13061029 SN - 2073-4425 VL - 13 IS - 6 PB - MDPI CY - Basel ER -