Phylogeny of the House Dust Mites and Relatives: Evolution or Devolution of Parasitism?

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

This project will use modern systematic methods to explain the origin and evolution of the house dust mites and their relatives. These mites, in the family Pyroglyphidae, are the primary cause of house dust allergy in millions of people. Pyroglyphid mites belong to a larger group of mites, the Psoroptidia, which includes almost exclusively parasites, living permanently on the bodies of birds and mammals. Most workers regard the Pyroglyphidae as the ancestral group for many parasite lineages, simply because this family includes the only non-parasitic psoroptidian species, i.e. the house dust mites and their relatives living in bird or mammal nests. Another hypothesis suggests the house dust mites have evolved from permanently parasitic ancestors, violating the evolutionary truism once a parasite, always a parasite. The primary objective of the study is to determine whether the parasitic mites form a single evolutionary lineage. Nucleotide sequence data from 12 different mitochondrial and nuclear genes obtained from at least 140 species representing most of the higher level diversity of psoroptidians and their relatives will be analyzed using the latest techniques. Furthermore, a number of new species have been and will be discovered during this study. These will be described and a new classification of the Pyroglyphidae proposed. This project will also provide training in systematics, molecular phylogenetics and parasitology to undergraduate, graduate and post-doctoral students. Over 20 undergraduate students and six doctoral and postdoctoral students have been trained in the PI's lab over the course of the last two funding cycles, over half of them women and several belonging to underrepresented minorities. This project also provides outreach to a younger generation of ornithologists and exposure to these collaborative ventures in parasite biology.