The following help file is in regards to the manuscript: 

"Crossing the divide: Admixture across the Antarctic Polar Front revealed by the brittle star Astrotoma agassizii."

Matthew P. Galaska1, Chester J. Sands2, Scott R. Santos1, Andrew R. Mahon3, and Kenneth M. Halanych1

1Department of Biological Sciences, Auburn University, 101 Rouse Life Science Building, Auburn, Alabama, USA; 2  Natural Environment Research Council, British Antarctic Survey, Cambridge, UK; 3 Department of Biology, Central Michigan University, Mount Pleasant, Michigan, USA.

Corresponding author: Matthew P. Galaska; Department of Biological Sciences, Auburn University, 101 Rouse Life Science Building, Auburn, AL, 36849, USA; fax 334-844-1645; mpg0009@auburn.edu, ken@auburn.edu

Compressed fasta files "Astrotoma_cleaned_fasta.rar" included have been screened for quality, size and presence of the AlfI restriction site.  This data is ready for further processing through STACKS software, Eli Meyer's (Oregon State University) scripts (https://github.com/Eli-Meyer) or through custom software. 

The following two STRUCTURE files were the final data matrices used for population genetic analyses.

The SNP file "astrotoma_94_955.stru" consists of 955 bi-allelic SNP loci using using the STACKS software package. Column one contains sample names, column two contains sampling locality information, and row one contains loci name information.  Each individual is coded in a single row.

The SNP file is coded numerically following the scheme 1=A, 2=G, 3=C, 4=T & -9=missing data.

This SNP file was used as an input files for all analyses following program manuals.