Correspondence to DP: dposada@uvigo.es. Competing interestsThe authors declare no competing interests. Online links 1.454sim: http://sourceforge.net/projects/bioinfo-454sim/ Computer simulation of genomic data has become increasingly popular for assessing and validating biological models or to gain understanding about specific datasets. Multiple computational tools for the simulation of next-generation sequencing (NGS) data have been developed in recent years, which could be used to compare existing and new NGS analytical pipelines. Here we review 23 of these tools, highlighting their distinct functionality, requirements and potential applications. We also provide a decision tree for the informed selection of an appropriate NGS simulation tool for the specific question at hand.

The study of hybrid zones resulting from Pleistocene vicariance is central in examining the potential of genetically diverged evolutionary units either to introgress and merge or to proceed with further isolation. The hybrid zone between two mitochondrial lineages of Chioglossa lusitanica is located near the Mondego River in Central Portugal. We used mitochondrial and nuclear diagnostic markers to conduct a formal statistical analysis of the Chioglossa hybrid zone in the context of tension zone theory. Key results are: (i) cline centres are not coincident for all markers, with average widths of ca. 2-15 km; (ii) heterozygote deficit was not observed across loci near the transect centre; (iii) associations of parental allele combinations ('linkage disequilibrium'R) were not detected either across loci or across the transect. These observations suggest that the Chioglossa hybrid zone is not a tension zone with strong selection against hybrids but instead one shaped mostly by neutral mixing. The patterns uncovered suggest a complex history of populations over a small scale that may be common in southern Pleistocene refugia.

Background The giant squid (Architeuthis dux; Steenstrup, 1857) is an enigmatic giant mollusc with a circumglobal distribution in the deep ocean, except in the high Arctic and Antarctic waters. The elusiveness of the species makes it difficult to study. Thus, having a genome assembled for this deep-sea–dwelling species will allow several pending evolutionary questions to be unlocked. Findings We present a draft genome assembly that includes 200 Gb of Illumina reads, 4 Gb of Moleculo synthetic long reads, and 108 Gb of Chicago libraries, with a final size matching the estimated genome size of 2.7 Gb, and a scaffold N50 of 4.8 Mb. We also present an alternative assembly including 27 Gb raw reads generated using the Pacific Biosciences platform. In addition, we sequenced the proteome of the same individual and RNA from 3 different tissue types from 3 other species of squid (Onychoteuthis banksii, Dosidicus gigas, and Sthenoteuthis oualaniensis) to assist genome annotation. We annotated 33,406 protein-coding genes supported by evidence, and the genome completeness estimated by BUSCO reached 92%. Repetitive regions cover 49.17% of the genome. Conclusions This annotated draft genome of A. dux provides a critical resource to investigate the unique traits of this species, including its gigantism and key adaptations to deep-sea environments.

Aim Cryptoblepharus is a genus of small arboreal or rock-dwelling scincid lizards, widespread through the Indo-Pacific and Australian regions, with a disjunct outlier in the Malagasy region. The taxonomy within this genus is controversial, with different authors ranking the different forms (now some 36) at various levels, from different species to subspecies of a single species, Cryptoblepharus boutonii. We investigated the biogeography and genetic differentiation of the Cryptoblepharus from the Western Indian Ocean region, in order to understand their origin and history.

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The deciphering of the process of genetic differentiation of species with insular distributions is relevant for biogeographical and conservation reasons. Despite their importance as old gondwanic islands and part of the western Indian Ocean biodiversity hotspot, little is known about the genetic structure of taxa from the Seychelles Islands. We have examined the patterns of structure and isolation within Urocotyledon inexpectata (Reptilia: Geckkonidae), an endemic species from this archipelago. Genetic diversity was screened from populations across the archipelago for both mitochondrial and nuclear genes. Gene genealogies and model-based inference were used to explore patterns and timings of isolation between the main lineages. High levels of genetic diversity were found for the mitochondrial and some of the nuclear markers. This species harbours at least two highly differentiated lineages, exclusively distributed across the northern and southern groups of the islands. The main split between these was dated back to the Miocene-late Pliocene, but isolation events throughout the Pliocene and Pleistocene were also inferred. Migration between groups of islands was apparently nonexistent, except for one case. The low dispersal capabilities of this species, together with the intrinsic fragmented nature of its geographical distribution, seem to have resulted in highly structured populations, despite the cyclic periods of contact between the different island groups. These populations may currently represent more than one species, making U. inexpectata another example of a morphologically cryptic lineage with deep genetic divergence within gekkonids. The observed patterns suggest a hypothetical biogeographic scenario (of a main north-south phylogeographic break) for the Seychelles that can be further tested with the exploration of the phylogeographic structure of other Seychellois taxa.

We report new primers for the amplification and sequencing of 11 nuclear markers in squamate reptiles and anuran amphibians (five in squamates, six in anurans). Ten out of the 11 loci are introns (three of which are linked) that were amplified using an exon-primed, introncrossing (EPIC) PCR strategy, whereas an eleventh locus spans part of a protein-coding gene. Squamate and anuran primers were initially developed for Lacerta schreiberi (Squamata: Lacertidae) and Pelodytes spp. (Anura: Pelodytidae), respectively. Cross-species amplification of the squamate markers was evaluated in four genera representing two additional families, whereas for anurans three genera corresponding to three additional families were tested. Three out of the five loci were successfully sequenced in all squamate taxa tested. Cross-amplification of the six anuran markers had lower, but still significant, success. We predict these markers will be of great utility for both population genetics and phylogenetic studies.