CENTENNIAL HONORS COLLEGE
Western Illinois University
Undergraduate Research Day 2016
PosterPresentation
DNABarcodingRevealsTwoCrypticSpeciesof“WhiteGrub”InfectingGreenSunfish.
ToriWorthen
FacultyMentor:ShawnMeagher
BiologicalSciences
Estimating parasite species diversity is important for understanding biodiversity. However it can be
difficult,duetotheexistenceofmorphologicallyidentical,butgeneticallydistinct“crypticspecies”.In
Spring Lake, IL, game fishes are infected with “white grub” (Posthodiplostomum minimum), and two
distinctsizesofwormsoccuringreensunfish(Lepomiscyanellus).IusedDNA“barcoding”todetermine
the number of white grub species that infect green sunfish. I collected eleven green sunfish by
electroshocking. Worms were removed from host livers and measured to the nearest 0.1 mm.
SequencesofmitochondrialcytochromeoxidaseI(COI)weredeterminedfor26wormsbytheCanadian
Centre for DNA barcoding (CCDB). Pairwise genetic distances were calculated between all sequences
andusedtoconstructaneighbor-joining(NJ)tree.IusedaBLASTsearchtoidentifythespeciesofeach
distinct group. The NJ revealed two genetically distinct groups. Mean genetic distance within groups
was0.008whilebetweengroupswas0.177.BLASTdeterminedthatoneoftheclusterswasLockesp.3
fromL.gibbosus(pumpkinseedsunfish)whilethesecondclusterwasLockesp.2,alsofromL.gibbosus.
Sizedifferedsignificantlybetweenthetwotypes(t=5.58.df=23,p<0.001);themean(±variance)for
sp.3was0.83(±0.049)andforsp.2was0.50(±0.006).Theseresultssuggestthatgreensunfishare
infectedbytwosimilar,butdistinct,species.SinceP.minimuminfects>20differentcentrachidhosts,
moredataareneededtoaccuratelydeterminespeciesnumberinthisgroup.
CENTENNIAL HONORS COLLEGE
Western Illinois University
Undergraduate Research Day 2016