Thank you to everyone who replied to my query about software to calculate mean allele size and variance from SSR data. The majority recommended MSA by DANIEL DIERINGER and CHRISTIAN SCHLÖTTERER (http://i122server.vu-wien.ac.at/MSA/MSA_download.html), and it did just what I wanted. GenAlEx will export an MSA input file from your GenAlEx-formatted spreadsheet. I hadn't needed these sort of statistics until Pickrell and Pritchard's treemix was released. Cheers, Alan Alan W. Meerow, Ph.D., Research Geneticist and Systematist USDA-ARS-SHRS, National Germplasm Repository 13601 Old Cutler Road, Miami, FL 33158 USA voice: 786-573-7075; FAX: 786-573-7110 email: alan.meerow@ars.usda.gov "Meerow, Alan"