The genome of Mesobuthus martensii reveals a unique adaptation model of arthropods

Abstract

Representing a basal branch of arachnids, scorpions are known as ‘living fossils’ that maintain an ancient anatomy and are adapted to have survived extreme climate changes. Here we report the genome sequence of Mesobuthus martensii, containing 32,016 protein-coding genes, the most among sequenced arthropods. Although M. martensii appears to evolve conservatively, it has a greater gene family turnover than the insects that have undergone diverse morphological and physiological changes, suggesting the decoupling of the molecular and morphological evolution in scorpions. Underlying the long-term adaptation of scorpions is the expansion of the gene families enriched in basic metabolic pathways, signalling pathways, neurotoxins and cytochrome P450, and the different dynamics of expansion between the shared and the scorpion lineage-specific gene families. Genomic and transcriptomic analyses further illustrate the important genetic features associated with prey, nocturnal behaviour, feeding and detoxification. The M. martensii genome reveals a unique adaptation model of arthropods, offering new insights into the genetic bases of the living fossils.

Ancestral whole-genome duplication in the marine chelicerate horseshoe crabs

“…As shown in Figure 3, Figure 4 and Supplementary Files 3 and 4, the genome of the scorpion Mesobuthus martensii (Cao et al, 2013) possesses multiple copies of many of the homeobox gene families studied here. Furthermore, the spider C. salei and the scorpion C. sculpturatus also possess multiple copies of several Hox cluster genes (Schwager et al, 2007;Sharma et al, 2014a).…”

Phylogenomic resolution of scorpions reveals multilevel discordance with morphological phylogenetic signal

“…Owing to the paucity of genomic resources available for Iurida, few existing datasets can presently be added to our supermatrices, and at considerable expense of matrix occupancy ( figure 3; electronic supplementary material, table S2). Adding four small datasets to our analyses (Scorpio maurus palmatus, Heterometrus petersii and two species of Scorpiops) indicated the monophyly of the genus Scorpiops with maximal nodal support, even though few genes (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) are available for the Scorpiops species; other relationships within 'Chactoidea' were not affected ( figure 3a). By contrast, addition of two scorpionids rendered the family Scorpionidae diphyletic in the best-scoring ML topology, with Scorpio maurus palmatus (represented by seven genes) nesting within the non-Liocheles hormurids (bootstrap resampling frequency of 69%; figure 3a).…”

“…For instance, despite significant research efforts on scorpion venoms by means of estimating species trees (EST), transcriptomic or genomic sequencing approaches, conclusions pertaining to the evolution of toxins remain tenuous due to an unknown underlying species tree (e.g. [27][28][29]). This also holds for investigations of various morphological characters [30][31][32].…”

Unique diversity of the venom peptides from the scorpion Androctonus bicolor revealed by transcriptomic and proteomic analysis

“…They function as host defense peptides. Until now, at least eleven defensins have been identified from the venom of scorpions, including TXKs2, defensin-1, -2, -3, -4, -5 and -6 from M. martensii Karsch [19], P56686 from A. australis and P41965 from Leiurus quinquestriatus hebraeus [60,61], Q6GU94 from Centruroides limpidus limpidus and Td defensin from Tityus discrepans. Here, we found that the transcripts of 4 unique novel defensins, which were referred to as AbDef-1 (KJ787323), AbDef-3 (KJ787318), AbDef-4 (KJ787319) and AbDef-5 (KJ787316), respectively, are present in the venom transcriptome of the scorpion A. bicolor.…”