kohanes are the direct descendants of AAron in the bible. they were the high priests who carried out the prayers and sacrifices. A big deal in days of the temple.
now they have no duties but temples like to call up (aliyah)the first person who is a kohane (katz/cohen etc)to read from the torah on sat. mornings.
genetic studies have shown a certain y gene is passed down among the male kdescendanats not the woman who donot have a y chromosome.you can google kkohane y chromosome if intereted ---gets detailed.