Dataset: DNA microsatellite alleles - Eelgrass ramets

SCUBA was used to sample Zostera marina in late summer 2014 from two coastal eelgrass meadows in the Gulf of Maine, USA, separated by approximately 48 km: Curlew Beach in Nahant, MA (hereafter CB) and Niles Beach in Gloucester, MA (hereafter NI). Samples were collected from three depths at each site: the center of the meadow (mid), and approximately 5 m from the inshore and offshore edges (shallow and deep, respectively); depth of our shallow, mid and deep samples was approximately 1, 3 and 5 m MLLW, respectively. At each depth, collected 8-10 flowering shoots, separated by at least 2 meters, were identified and collected. The genetic structure of neighboring plants around each flowering shoot was characterized by haphazardly selecting up to 10 vegetative shoots from within a 0.25-m² quadrat set around each focal flowering shoot (n = ~250 shoots per site). Leaf tissue was preserved in silica or frozen until DNA extraction.

Molecular methods:
DNA was extracted from leaf tissue by grinding each sample with a Retsch mixer mill MM400 and using the Omega Bio-Tek E.Z.N.A.® Plant DNA Kit. Each leaf sample was genotyped using 12 microsatellite loci developed for Zostera marina, multiplexed in three 11 ul PCR reactions. Each reaction consisted of 1 ul DNA template, 5 ul 2X Type-It multiplex master mix (Qiagen), and 0.25 ul of each 10 uM primer. PCR cycling conditions included initial activation/denaturation at 95°C for 5 min, followed by 28 cycles of 95°C for 30 sec, 60°C for 90 sec, and 72°C for 30 sec, and final extension at 60°C for 30 min. PCR products were separated on a 3730xl Genetic Analyzer (Applied Biosystems) at the Yale University DNA Analysis Facility, and fragment analysis was performed using GeneMarker version 2.6 (SoftGenetics).