Coevolution of house mice and intracellular parasites in a hybrid zone
Final Report Abstract
The central question addressed in the funded project was whether hybridization and introgression between species are enhanced or limited by the presence of parasites. To answer this question we had planned to investigate the intensity of parasite infections in natural populations of hybrid house mice. It has also become necessary to elucidate the identity, population structure and virulence of these parasites. As basic prerequisite of the project, we were able to localize the house mouse hybrid zone (a tension zone between the subspecies Mus musculus domesticus and Mus m. musculus) East of Berlin. Within mice in this zone we found three parasite species of the genus Eimeria: E. ferrisi, E. falciformis and E. vermiformis, which are clearly distinct and do not hybridize themselves. We were able to consolidate previous findings showing lower intensity of pinworms in hybrid mice. As a more novel result we show lower intensities of the (relatively more pathogenic) Eimeria spp. in hybrid hosts than in parental mice. We argue that this (i.e. parasites with different virulence, niches and natural history showing the same effect) settles long standing debates on the effect of hybridization on resistance against parasites. We were, however, not able to measure a health effect (i.e. impact on body condition) of parasites under natural conditions. For parasites to have an effect on hybridisation, resistance would need to result in increased fitness of the host. This is not clear, as fitness effects of resistance are often mediated by infection tolerance. We thus performed infection experiments to investigate whether resistance against the prevalent E. ferrisi and E. falciformis results in a mitigation of negative effects on health of hybrid mice during infection. In other words: whether resistance and tolerance against the parasite correlate. We found that while against the relatively less virulent E. ferrisi resistance improves health, against the more virulent E. falciformis resistance leads to detrimental health outcomes. This leaves the question of a fitness effect on hybrid hosts open, but provides a clear scope for investigation in follow up projects addressing this question. We did not find the original suspicion of hybridizing parasites in a host hybrid zone to be fulfilled. We, however, found closely related parasites showing differences in whether hosts should better resist or tolerate them in order to maintain good health. This will allow us in future to address the question why and how hosts’ pathological immune reactions often seem to damage health more than warranted by the pathogen. While some of the original research ideas had to be reconsidered, overall the results gathered during the first funding period establish a novel host-parasite system in the natural environment on which work on the molecular and cellular (immunological) level is equally attractive.
Publications
- 2017. ‘Dual RNA-Seq Reveals No Plastic Transcriptional Response of the Coccidian Parasite Eimeria Falciformis to Host Immune Defenses’. BMC Genomics 18 (1): 686
Ehret, Totta, Simone Spork, Christoph Dieterich, Richard Lucius, and Emanuel Heitlinger
(See online at https://doi.org/10.1186/s12864-017-4095-6) - 2019. ‘A Novel Non-Invasive Method to Detect RELM Beta Transcript in Gut Barrier Related Changes during a Gastrointestinal Nematode Infection’. Frontiers in Immunology 10: 445
Ahmed, Norus, Emanuel Heitlinger, Nicole Affinass, Anja A. Kühl, Natasa Xenophontos, Victor Hugo Jarquin, Jenny Jost, Svenja Steinfelder, and Susanne Hartmann
(See online at https://doi.org/10.3389/fimmu.2019.00445) - 2019. ‘Detection and Quantification of House Mouse Eimeria at the Species Level – Challenges and Solutions for the Assessment of Coccidia in Wildlife’. International Journal for Parasitology: Parasites and Wildlife 10 : 29–40
Jarquín-Díaz, Víctor Hugo, Alice Balard, Jenny Jost, Julia Kraft, Mert Naci Dikmen, Jana Kvičerová, and Emanuel Heitlinger
(See online at https://doi.org/10.1016/j.ijppaw.2019.07.004) - 2019. ‘Generalist Eimeria Species in Rodents: Multilocus Analyses Indicate Inadequate Resolution of Established Markers’
Jarquín-Díaz, Víctor Hugo, Alice Balard, Anna Mácová, Jenny Jost, Tabea Roth von Szepesbéla, Karin Berktold, Steffen Tank, Jana Kvičerová, and Emanuel Heitlinger
(See online at https://doi.org/10.1101/690487) - 2020. ‘Coupling between Tolerance and Resistance for Two Related Eimeria Parasite Species’. Ecology and Evolution
Balard, Alice, Víctor Hugo Jarquín‐Díaz, Jenny Jost, Vivian Mittné, Francisca Böhning, Ľudovít Ďureje, Jaroslav Piálek, and Emanuel Heitlinger
(See online at https://doi.org/10.1002/ece3.6986) - 2020. ‘Intensity of Infection with Intracellular Eimeria Spp. and Pinworms Is Reduced in Hybrid Mice Compared to Parental Subspecies’. Journal of Evolutionary Biology 33 (4): 435–48
Balard, Alice, Víctor Hugo Jarquín‐Díaz, Jenny Jost, Iva Martincová, Ľudovít Ďureje, Jaroslav Piálek, Miloš Macholán, Joëlle Goüy de Bellocq, Stuart JE Baird, and Emanuel Heitlinger
(See online at https://doi.org/10.1111/jeb.13578)
