A phylogenomic approach to dating an ancient insect lineage

Aphids, thrips and lice are pests of agricultural and medical importance but the evolution of this diverse group of insects is poorly known. How are these plant and animal parasites related to one another? When did these parasites originate? These are the questions this project will investigate. The recent advances in DNA technology combined with the decreased costs of these methods make it possible to gather a large amount of DNA data to elucidate the relationships between these insect pests. We are also able to develop new analytical methods that can deal with the huge amount of data generated. As a result, we will now be able to reliably determine the origin and evolution of this important group of insects.

Traditional PCR approaches for building matrices of a few mitochondrial and nuclear markers have failed to resolve deep phylogenetic relationships in the hemipteroid assemblage, a diverse group of insects of agricultural and medical importance. The increased availability of genomic data is pushing taxonomy and phylogenetics into a new era by enabling phylogenetic reconstruction based on more than 100 genes, but gene trees are often confounded by paralogy and these genes tend to be removed a priori from phylogenomic studies. Gene tree parsimony methods for phylogenomic reconstructions can deal with paralogy but better bioinformatics tools need to be developed. The method also needs to be compared to more widely used supertree and supermatrix approaches. We will gather additional genomic data using an EST approach and in conjunction with the development of improved gene tree methods, we will determine the phylogenetic relationships of the neglected hemipteroid assemblage and compare reconstruction methodologies. With this data we will reliably estimate the origins of parasitism and specialization in this ancient clade.