Comparative genomic analysis of co-occurring hybrid zones of house mouse
parasites Pneumocystis murina and Syphacia obvelata using genome
polarisation
Abstract
Parasites are expected to hybridise in similar ways to free living
organisms, although this may be modified by their reduced genome
architecture. Recombinant strains and taxa of hybrid origin can be
studied in nature where hosts come into secondary contact. Here we apply
genome-wide analysis to parasites from a contact previously
characterised for many individuals using classical markers. The host
contact is the European house mouse hybrid zone; the parasites are lung
fungus Pneumocystis and gut pinworm Syphacia. The multilocus and
multi-individual datasets are broadly consistent in scale and centering.
Whole mitogenome comparisons confirm earlier suggestions that parasite
divergence is low compared to their hosts, perhaps due to reduced genome
stabilising selection. In the recombining genome we are able to show
blocks of parasite genome of alternating host origin, including one
Pneumocystis strain which appears to be an F3+ cross and one recombinant
Syphacia strain found over multiple localities. Functional analyses of
introgressing genes show enrichment for genes likely important for
parasitic lifestyle.