Date Thesis Awarded

5-2020

Access Type

Honors Thesis -- Access Restricted On-Campus Only

Degree Name

Bachelors of Science (BS)

Department

Biology

Advisor

Kurt Williamson

Committee Members

Shantá Hinton

Henry Hart

Abstract

Viruses are ubiquitous across diverse ecosystems and represent the largest reservoir of genetic diversity on the planet. Bacteriophages, viruses that infect and replicate within bacteria, play important roles in global geochemical cycles and microbial evolution. Despite significant advances in knowledge regarding phages in aquatic systems, viruses in soil remain relatively unexplored. Particularly, little is known regarding the presence and distribution of various phage families in conventional, unsaturated soil environments. Marker genes, which are indicative of a specific viral group, are an efficient, established method of investigating genetic diversity in phages without requiring the costly techniques of metagenomics. This study utilized four marker genes to study the genetic diversity of viruses in soil. Forty-four soil samples and two aquatic samples were collected. Following DNA extraction, amplification of marker genes was attempted through polymerase chain reaction using different primer sets. Three of the marker genes, B1, MCP, and T7-like DNA polymerase, failed to amplify in any of the soil samples. The fourth marker gene, g23, successfully amplified and positive samples were selected for further analysis. Following cloning and transformation, a total of forty g23 clones were obtained and sequenced via Sanger sequencing. Sequences from Virginia soils were compared to g23 clones from previous studies in freshwater, marine, paddy field, and upland black soil environments. This study discovered and described novel genetic diversity within the T4-like phage family through the g23 marker gene. Future research should explore viral biogeography and population ecology in order to better understand the role of phages in soil.

Recommended Citation

Dar, Nakul, "Investigating the Genetic Diversity of Viruses in Soil Using a Marker Gene Approach" (2020). Undergraduate Honors Theses. William & Mary. Paper 1482.
https://scholarworks.wm.edu/honorstheses/1482