 Blackburn and her student Carol Greider later discovered the enzyme telomerase that maintains the lengths of the protective telomeric sequences and identified its role in aging.Joseph Gall currently heads the Gall Lab, a component of the Department of Embryology in the Carnegie Institution for Science, in Maryland.Gall is credited with encouraging women biologists, a group sometimes called "Gall's Gals", in an era when this was relatively uncommon.