DOI: 10.5061/dryad.9cnp5hqsz
title: Sepiola COI and Vibrio gapA gene sequences

description: Symbiotic marine bacteria that are transmitted through the environment are
 susceptible to possible abiotic factors (salinity, temperature, physical
 barriers) that separate them from their hosts. Given that many symbioses
 are driven by host specificity, environmentally transmitted symbionts can
 alter symbiont preference depending on conditions over space and time. In
 order to determine whether the population structure of environmentally
 transmitted beneficial associations reflects host specificity or
 biogeography, we analyzed the genetic structure of Sepiola atlantica
 (Cephalopoda: Sepiolidae) and their Vibrio symbionts (V. fischeri and V.
 logei) in four Galician Rías (Spain). This geographical location is
 characterized by a jagged coastline with a deep-sea entrance into the
 land, ideal for testing whether such population barriers exist due to
 genetic isolation. We used haplotype estimates combined with nested clade
 analysis to determine the genetic relatedness for both S. atlantica and
 Vibrio bacteria. Analyses of molecular variance (AMOVA) were used to
 estimate variation within and between populations for both host and
 symbiont genetic data. Our analyses reveal a low percentage of variation
 among and between host populations, suggesting that these populations are
 panmictic. In contrast, Vibrio symbiont populations show a certain degree
 of genetic structure, demonstrating that the hydrology of the rias is
 driving bacterial distribution (and not host specificity). Thus, for
 environmentally transmitted symbioses such as the sepiolid squid-Vibrio
 association, abiotic factors can be a major selective force for
 determining the population structure of one of the partners.
description: Samples were obtained via SCUBA at approximately 6 to 10 meters
 deep at each site. Animals were transported and maintained at the Centro
 de Investigación Mariña-Estación de Ciencias Mariñas de Toralla
 (CIM-ECIMAT) facilities and subsequently euthanized one day later
 following protocols previously approved by the Animal Experimentation
 Ethics Committee from the University of Vigo (Spain) and the IACUC at New
 Mexico State University (NMSU; Andrews et al., 2013; Moltschaniwskyj et
 al., 2007). Single colonies of <em>Vibrio </em>bacteria were
 isolated from host light organs that were removed via ventral dissection
 and homogenized and diluted onto seawater tryptone agar (SWT; 0.5%
 tryptone, 0.3% yeast extract, 0.3% glycerol, 1.5% agar, and 70% seawater
 at 32 ppt.
description: # Sepiola COI and Vibrio gapA gene sequences
 [https://doi.org/10.5061/dryad.9cnp5hqsz](https://doi.org/10.5061/dryad.9cnp5hqsz) The dataset contains the cytochrome c oxidase subunit (COI) gene sequences from the host, *Sepiola atlantica*, and the glyceraldehyde 3-phosphate dehydrogenase A (gapA) gene sequences from the symbiont, *Vibrio* sp. ## Description of the data and file structure The samples were taken on the NW coast of Spain, in an area called Rias Gallegas or Galician Rias. The populations of both the host and the symbiont correspond to five different sampling locations (north to south): Ría de Ferrol, Ría de Corcubión (G), Ría de Arousa (A), Ría de Aldán (AD) and Ría de Vigo (AM).