Pushing the limits of whole genome amplification: successful sequencing of RADseq libraries from single micro-hymenoptera (Chalcidoidea, Trichogramma)

A major obstacle to high-throughput genotyping of micro-hymenoptera is their small size. As species are difficult to discriminate and because complexes may exist, the sequencing of a pool of specimens is hazardous. Thus, one should be able to sequence pangenomic markers (e.g. RADtags) from a single specimen. To date, whole genome amplification (WGA) prior to library construction is still a necessity as only ca 10ng of DNA can be obtained from single specimens. However this amount of DNA is not compatible with manufacturer's requirements for commercialised kits. Here we tested the accuracy of the GenomiPhi kit V2 on Trichogramma wasps by comparing RAD libraries obtained from the WGA of single specimens (generation F0 and F1, ca 1 ng input DNA for the WGA) and a biological amplification of genomic material (the pool of the progeny of the F1 generation). Globally, we found that ca 99% of the examined loci (up to 48,189; 109 bp each) were compatible with the mode of reproduction of the studied model (haplodiploidy) or a Mendelian inheritance of alleles. The remaining 1% (ca 0.01% of the analysed nucleotides) could represent WGA bias or other experimental / analytical bias. This study shows that the multiple displacement amplification method on which the GenomiPhi kit relies, could also be of great help for the high-throughput genotyping of micro-hymenoptera used for biological control or other organisms from which only a very low amount of DNA can be extracted such as human disease vectors (e.g. sand flies, fleas, ticks etc.).