Retrophylogenomics place tarsiers on the evolutionary branch of anthropoids

One of the most disputed issues in primate evolution and thus of our own primate roots, is the phylogenetic position of the Southeast Asian tarsier. While much molecular data indicate a basal place in the primate tree shared with strepsirrhines (prosimian monophyly hypothesis), data also exist supporting either an earlier divergence in primates (tarsier-first hypothesis) or a close relationship with anthropoid primates (Haplorrhini hypothesis). The use of retroposon insertions embedded in the Tarsius genome afforded us the unique opportunity to directly test all three hypotheses via three pairwise genome alignments. From millions of retroposons, we found 104 perfect orthologous insertions in both tarsiers and anthropoids to the exclusion of strepsirrhines, providing conflict-free evidence for the Haplorrhini hypothesis, and none supporting either of the other two positions. Thus, tarsiers are clearly the sister group to anthropoids in the clade Haplorrhini

Genomic and morphological evidence converge to resolve the enigma of strepsiptera

The phylogeny of insects, one of the most spectacular radiations of life on earth, has received considerable attention [1-3]. However, the evolutionary roots of one intriguing group of insects, the twisted-wing parasites (Strepsiptera), remain unclear despite centuries of study and debate [1, 2, 4-11]. Strepsiptera exhibit exceptional larval developmental features, consistent with a predicted step from direct (hemimetabolous) larval development to complete metamorphosis that could have set the stage for the spectacular radiation of metamorphic (holometabolous) insects [1, 12, 13]. Here we report the sequencing of a Strepsiptera genome and show that the analysis of sequence-based genomic data (comprising more than 18 million nucleotides from nearly 4,500 genes obtained from a total of 13 insect genomes), along with genomic metacharacters, clarifies the phylogenetic origin of Strepsiptera and sheds light on the evolution of holometabolous insect development. Our results provide overwhelming support for Strepsiptera as the closest living relatives of beetles (Coleoptera). They demonstrate that the larval developmental features of Strepsiptera, reminiscent of those of hemimetabolous insects, are the result of convergence. Our analyses solve the long-standing enigma of the evolutionary roots of Strepsiptera and reveal that the holometabolous mode of insect development is more malleable than previously thought. © 2012 Elsevier Ltd

Data from: Oligonucleotide primers for targeted amplification of single-copy nuclear genes in apocritan Hymenoptera

BACKGROUND: Published nucleotide sequence data from the mega-diverse insect order Hymenoptera (sawflies, bees, wasps, and ants) are taxonomically scattered and still inadequate for reconstructing a well-supported phylogenetic tree for the order. The analysis of comprehensive multiple gene data sets obtained via targeted PCR could provide a cost-effective solution to this problem. However, oligonucleotide primers for PCR amplification of nuclear genes across a wide range of hymenopteran species are still scarce. FINDINGS: Here we present a suite of degenerate oligonucleotide primer pairs for PCR amplification of 154 single-copy nuclear protein-coding genes from Hymenoptera. These primers were inferred from genome sequence data from nine Hymenoptera (seven species of ants, the honeybee, and the parasitoid wasp Nasonia vitripennis). We empirically tested a randomly chosen subset of these primer pairs for amplifying target genes from six Hymenoptera, representing the families Chrysididae, Crabronidae, Gasteruptiidae, Leucospidae, Pompilidae, and Stephanidae. Based on our results, we estimate that these primers are suitable for studying a large number of nuclear genes across a wide range of apocritan Hymenoptera (i.e., all hymenopterans with a wasp-waist) and of aculeate Hymenoptera in particular (i.e., apocritan wasps with stingers). CONCLUSIONS: The amplified nucleotide sequences are (a) with high probability from single-copy genes, (b) easily generated at low financial costs, especially when compared to phylogenomic approaches, (c) easily sequenced by means of an additionally provided set of sequencing primers, and (d) suitable to address a wide range of phylogenetic questions and to aid rapid species identification via barcoding, as many amplicons contain both exonic and fast-evolving intronic nucleotides

Data from: Oligonucleotide primers for targeted amplification of single-copy nuclear genes in apocritan Hymenoptera

BACKGROUND: Published nucleotide sequence data from the mega-diverse insect order Hymenoptera (sawflies, bees, wasps, and ants) are taxonomically scattered and still inadequate for reconstructing a well-supported phylogenetic tree for the order. The analysis of comprehensive multiple gene data sets obtained via targeted PCR could provide a cost-effective solution to this problem. However, oligonucleotide primers for PCR amplification of nuclear genes across a wide range of hymenopteran species are still scarce. FINDINGS: Here we present a suite of degenerate oligonucleotide primer pairs for PCR amplification of 154 single-copy nuclear protein-coding genes from Hymenoptera. These primers were inferred from genome sequence data from nine Hymenoptera (seven species of ants, the honeybee, and the parasitoid wasp Nasonia vitripennis). We empirically tested a randomly chosen subset of these primer pairs for amplifying target genes from six Hymenoptera, representing the families Chrysididae, Crabronidae, Gasteruptiidae, Leucospidae, Pompilidae, and Stephanidae. Based on our results, we estimate that these primers are suitable for studying a large number of nuclear genes across a wide range of apocritan Hymenoptera (i.e., all hymenopterans with a wasp-waist) and of aculeate Hymenoptera in particular (i.e., apocritan wasps with stingers). CONCLUSIONS: The amplified nucleotide sequences are (a) with high probability from single-copy genes, (b) easily generated at low financial costs, especially when compared to phylogenomic approaches, (c) easily sequenced by means of an additionally provided set of sequencing primers, and (d) suitable to address a wide range of phylogenetic questions and to aid rapid species identification via barcoding, as many amplicons contain both exonic and fast-evolving intronic nucleotides

Amplicons_NT.tar

Supplementary File Archive: "Amplicons_NT.tar.gz." Multiple nucleotide sequence alignments in FASTA format of expected amplicons when applying the PCR oligonucleotide primer pairs inferred in our study. Each multiple nucleotide sequence alignment contains the nucleotide sequence of each of the nine species of Hymenoptera whose genomes we analyzed plus the position and nucleotide sequence (with IUPAC ambiguity code; complement sequence of reverse primer) of the inferred forward and reverse PCR oligonucleotide primer. Anatomy of the file names: [Identifier of ortholog group]_[Identifier of oligonucleotide primer pair specific to ortholog group]_[Identifier of recommended pair of sequencing primers].NT.fas For example, the file name "HOG2939_01_B.NT.fas" contains the nucleotide sequences expected to be amplified from the genes belonging to ortholog group "HOG2939" when using the first oligonucleotide primer pair that has been inferred for this ortholog group and the sequencing oligonucleotide primer pair B. HOG stands for "Hymenoptera Ortholog Group"

Rating of obtained polymerase chain reaction (PCR) products.

<p>Rating of the PCR products obtained from using the degenerate oligonucleotide primers shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039826#pone-0039826-t003" target="_blank">Table 3</a> to amplify ten target genes in six apocritan Hymenoptera. ++  =  target PCR product in excess. +  =  target PCR product sufficient for direct sequencing. +/−  =  target PCR product insufficient for direct sequencing. –  =  no target PCR product. (?)  =  unclear whether or not PCR products include amplicon of target gene.</p>*<p>Secondary PCR amplification product likely hampering direct sequencing.</p

Hypothesized phylogenetic relationships of apocritan Hymenoptera studied in this investigation [4], [12].

<p>Taxa with sequenced genomes are highlighted in green; their genome sequences were analyzed to identify single-copy genes and to design degenerate oligonucleotide PCR primers. DNA of non-highlighted species was used to assess the functionality of the inferred PCR and sequencing primers.</p

European Nucleotide Archive accession numbers for all sequences generated from primer testing.

<p>European Nucleotide Archive accession numbers for all sequences generated from primer testing.</p

Empirically evaluated degenerate oligonucleotide PCR primer pairs.

<p>The ten degenerate oligonucleotide primers were tested with the respective binding sites for sequencing primer HOG-Seq-A (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039826#pone-0039826-t002" target="_blank">Table 2</a>) attached to the 5′ end and used to amplify ten target genes in six apocritan Hymenoptera. <i>d</i>  =  degree of degeneration. <i>T</i>_m  =  approximate melting temperature [°C].</p