Dataset: Gnathiid blood meal identification results

Fieldwork was conducted between May and August of 2015 and 2016. The coordinates for each site are as follows: 17°57’17.59” N, 67°3’9.96” W (Site 1: Cayo Enrique, La Parguera, PR), 17°56’33.60” N, 67°4’41.02” W (Site 2: San Cristobal, La Parguera, PR, 18°19’3.54” N, 65°19’5.06” W (Site 3: Tamarindo Bay, Culebra, PR), 18°20’25.08” N, 64°58’39.77” W (Site 4: Brewer’s Bay, St. Thomas, USVI), and 18°19’2.17” N, 64°43’21.09” W (Site 5: Great Lameshur Bay, St. John, USVI).

Sites off the coast of La Parguera, PR were accessed using powerboats (approximately 14 – 16 feet) at the Isla Magueyes Marine Laboratories of the University of Puerto Rico at Mayagüez. Our site in Tamarindo Bay, Culebra, PR was accessed from shore and did not require boat use. Sites in St. Thomas and St. John, USVI were accessed from shore and using small powerboats supplied by the University of the Virgin Islands, as necessary. 

Gnathiids were collected using lighted plankton traps following the protocol of Artim and Sikkel, 2016. Briefly, light traps were deployed on shallow reefs overnight and sorted to remove visibly fed juvenile gnathiids (pranizae). Specimens were preserved in 100 percent molecular grade ethanol and stored at less than -20 degrees C until being shipped to the Arkansas Biosciences Institute (Arkansas State University, Jonesboro, AR) where they were kept at -80 degrees C.

DNA was extracted from individually fed gnathiids using the PureLink® Genomic DNA extraction kit (Invitrogen, Carlsbad, CA), following the manufacturer’s ‘Mammalian Tissue and Mouse/Rat Tail Lysate’ protocol. Purified DNA was concentrated from 50 microliters (µL) to 15 µL using the ThermoSavant ISS110 SpeedVac® System (Thermo Fisher Scientific, Wilmington, DE).

PCR reactions were carried out following the protocol of Hendrick et al., 2019. Primers of the mitochondrial gene cytochrome c oxidase subunit 1 (cox1, COI, or MT-CO1) (5’-TCAACYAATCAYAAAGATATYGGCAC-3’; 5’-ACTTCYGGGTGRCCRAARAATCA-3’). PCR reactions included 10 µL of concentrated template DNA and 10 µL of master mix solution containing forward and reverse COI primers, 1.25 units GoTaq Hot Start Polymerase, 1x buffer with 1.5 mM MgCl2 (Promega, Madison, WI), and 0.2 mM dNTP Mix (Thermo Fisher Scientific, Wilmington, DE). A Veriti 96 Well Thermal Cycler (Applied Biosystem, Foster City, CA) was used to carry out PCR reactions with the following thermocycling conditions: initial denaturation step of 94 degrees C for 2 minutes, 30 cycles of 96 degrees C for 20 seconds, 55 degrees C for 20 seconds, and 72 degrees C for 45 seconds, and a final extension step of 72 degrees C for 7 minutes.

ExoSAP-IT (Applied Biosystem, Foster City, CA) was used for enzymatic digestion of excess PCR reagents prior to Sanger sequencing. All samples were sent to the University of Chicago Comprehensive Cancer Center, DNA Sequencing & Genotyping Facility for sequencing. For samples that did not result in successful host identification after one PCR reaction, a second PCR was performed using 10 µL of PCR product from the initial PCR reaction as template DNA.

Known Issues:
The DNA sequences within this dataset originated from partially digested blood meals of gnathiid isopods and should not be used as a reference for the comparison of sequence mutations.