Using hybrid bait capture to investigate parasite diversity and related immune genes in the Trinidad guppy (Poecilia reticulata)

Abstract

The Trinidad guppy (Poecilia reticulata) serves as a model organism in evolutionary biology due to its rapid generation time, live birth, and ability to evolve quickly in response to environmental pressures. These features make guppies ideal for studying the interplay between predation, parasitism, and evolutionary adaptation. In their native habitats, guppies exhibit distinct colour variations and morphological adaptations based on predation pressure, with high predation environments typically selecting for drab coloration and rapid life histories. Parasitism also plays a crucial role in guppy evolution by affecting survival and reproductive success. This study investigates hybrid bait capture to simultaneously analyse guppy and parasite DNA on a pilot set of fish. The aim is to trial the ability of hybrid bait captures to quantify parasite diversity and community composition across different guppy populations and predation environments, while also retrieving and sequencing guppy immune genes. I found that this methodology uncovers a more comprehensive view of the diversity present on guppies using a combination of probes to target the 18S and COI gene regions. Contrary to previous studies, I found that Trematoda is just as prevalent as monogeneans in our sample size. This suggests the focus on Monogenea entirely as the primary parasite from previous studies may offer an incomplete view. Additionally, guppy gene retrieval works well alongside metabarcoding using this methodology as I retrieved on average 98% of the target guppy genes. This research bridges the gap in understanding the genetic basis of guppy-parasite interactions, offering a novel approach to examining the co-evolutionary dynamics between hosts and parasites. As both the metabarcoding and guppy gene were retrieval successful, this study establishes hybrid bait capture as a viable approach for future studies to examine parasite-host interactions.

Date of Award	26 Mar 2025
Original language	English
Awarding Institution	Bangor University
Supervisor	Alexander Papadopulos (Supervisor) & Amy Ellison (Supervisor)