Founder effects and species introductions: A host versus parasite perspective

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)
April M. H.,Haram,Linsey E.,Altman,Irit,Kennedy,Kristin, Blakeslee (Creator)
East Carolina University (ECU )
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Abstract: Species colonizations (both natural and anthropogenic) can be associated with geneticfounder effects, where founding populations demonstrate significant genetic bottlenecks compared to native populations. Yet, many successfully established free-livingspecies exhibit little reduction in genetic diversity-”possibly due to multiple founding events and/or high propagule pressure during introductions. Less clear, however, is whether parasites may show differential signatures to their free-living hosts.Parasites with indirect life cycles may particularly be more prone to founder effects(i.e., more genetically depauperate) because of inherently smaller founding populations and complex life cycles. We investigated this question in native (east coast) andintroduced (west coast) North American populations of a host snail Tritia obsoleta(formerly Ilyanassa obsoleta, the eastern mudsnail) and four trematode parasite species that obligately infect it. We examined genetic diversity, gene flow, and population structure using two molecular markers (mitochondrial and nuclear) for the hostand the parasites. In the host snail, we found little to no evidence of genetic foundereffects, while the trematode parasites showed significantly lower genetic diversityin the introduced versus native ranges. Moreover, the parasite's final host influencedinfection prevalence and genetic diversity: Trematode species that utilized fish asfinal hosts demonstrated lower parasite diversity and heightened founder effects inthe introduced range than those trematodes using birds as final hosts. In addition,inter-regional gene flow was strongest for comparisons that included the putativehistorical source region (mid-Atlantic populations of the US east coast). Overall, ourresults broaden understanding of the role that colonization events (including recentanthropogenic introductions) have on genetic diversity in non-native organisms byalso evaluating less studied groups like parasites.

Additional Information

Language: English
Date: 2019
gene flow, genetic bottleneck, introduction vector, invasion, life cycle, propagule pressure, trematode

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