I'm not even sure what a 'spirit' is
I can only describe it in the way I understand it and this is yielded from the Holy Bible.
It is the part of us that, though invisible, is a product of the spiritual nature of the universe. I would go as far as to say that every expression is fired by our nervous/spiritual nature and so...as hysterical behaviour proves...we can waste it wildly.
Our inner nervous/spiritual nature must come from somewhere. Some is delivered by chemical interactions but Jesus, who speaks on behalf of Almighty God, tells us that we can earn it by righteous good behaviour.
If we say that it is part of the nervous/electric behaviour of the replicating living cell then we can see that it is a spiritual representation of our own being and...it seems...if we talk to Jesus Christ's word...it can be the force behind resurrection, behind everlasting life...and the force behind genetic repair in this life. We just have to believe those who love us.