How is the Orthodox priesthood different from the Old Testament priesthood?

When we talk about Christ and the mystical supper, the priesthood that we receive, according to St Paul, is the priesthood of Christ. The Old Testament priesthood was based on genealogy. So if you were born into a family that you would be a priest, you would be a priest through that genealogical circumstance that you were born into, and you'd be elevated to the rank of priest. This is not the case in the church. The case in the church is that those who are priests are priests through the laying on of apostolic hands that has been handed down. This is even what St Paul says in his epistle, where he says, I laid hands on men. I appointed, in the Greek he says, I appointed bishops and priests through the ordination and the laying on of hands. This concept is undisputed in the early church. It is an impossibility not to understand this from reading the church fathers.