Grace Havern
Research Mentor: Cheyenne Graham
Mentor Department: Ecology and Evolutionary Biology, LSA
Author(s): Not Available
Session: Session 3 (11:00 AM – 11:50 AM)
Presentation Type: Poster 11
Abstract
Rodents of the genus Rattus are among the most successful invasive species, with Rattus rattus and Rattus tanezumi establishing widespread populations due to their commensal relationship with humans. Invasive Rattus species are also known reservoirs of zoonotic pathogens, making them ecologically and epidemiologically significant. Recent studies have identified hybridization between R. rattus and R. tanezumi in multiple regions, yet the extent of genetic admixture in North American populations remains unclear. This study assesses hybridization between R. rattus and R. tanezumi in Los Angeles, California using museum specimens. It investigates how hybridization shapes immune gene variation, particularly in the major histocompatibility complex (MHC) by assessing parasite diversity in hybrid and non-hybrid individuals. DNA was extracted from liver tissue, and species identification was conducted using mitochondrial cytochrome b (CytB). Preliminary mitochondrial analyses suggest evidence of hybridization, and nuclear markers are being further assessed for genetic admixture. Following the discovery of hybridization, parasites were morphologically identified, extracted and sequenced for further identification. In the context of hybrid vigor, we hypothesize that hybrids of R. rattus and R. tanezumi will have lower parasite diversity compared to the parental individuals. Understanding the extent of hybridization in this system is critical since genetic introgression may influence traits such as pathogen susceptibility. This work provides novel insights into the role of hybridization in immune system evolution and pathogen resistance, with broader implications for zoonotic disease transmission and host-pathogen interactions.
