DNA for Genealogy: Why test? What you can learn. Health results at moderate cost. Explore differences among testing companies. The importance of adding a tree to your results. Extending your results with gedmatch. Special Interest Group Leader Sue Mueller teaches this class the fourth Tuesday of every month except December. Sessions are free, and open to the public, but please register in advance at the Erie Public Library website, http://www.erielibrary.org/events.