In Parashas Emor we are taught various laws that pertain to Kohanim. We learn about their avodah, how they become tamei, who they could marry, what happens if they have a deformity, etc.
A recent study by Dr. Karl (Kalman) Skorecki, a researcher at the University of Toronto and the Rambam-Technion Medical Center in Haifa, revealed that Kohanim share a common set of genetic characteristics that have been passed down from their common ancestor, Aharon HaKohein.