I think you may detect the contradiction between those two statements, PSacramento. If the genealogies were retained in the Christian writings because they lent credibility to the messianic claim of Jesus of Nazareth from the Hebrew perspective then it does not follow that the Hebrew perspective would be later downplayed. It sounds too much like sucking people into listenting to The Truth by starting with a lie.
It was downplayed later when the Gospel was preached to the gentiles, to whom the whole "Jewish Messiah" thing was irrelevant.
Here's the upshot. Ready? Fundamentalist Christian groups, and I will include the Watchtower as much as they would object, look down upon what they call cafeteria Christians precisely for this reason. Christianity is based 100% (one hundred percent) on the Bible, there is no other source. But people who consider themselves non-fundamentalist Christians will accept less than 100% of the Bible as fact. Rejection of the Adam and Eve story verbatim when it has been presented as fact together with the genealogy of Jesus of Nazareth, also presented as fact, is rationalisation of one's faith, picking and choosing between what is credible to him and what is not.
Fact is, nowhere does the bibel state that in of itself, in 100% totality, is it to be seen as inerrant and the word of God, on the contrary, we are told in the bibel to test everything and told that the scribes did indeed alter the word of God.
I agree, the Genesis story is not credible. It crumbles under the weight of massive contradictory evidence. But I also agree that the very basic tenets of Christianity fall apart without it, and it is for this reason I am not a Christian.
Genesis is the creation of the world in "baby talk" for ancient man, it is not science nor is it an explanation of the process by whcih God created the universe, it is a combination of stories ( probably two) that were passed on via oral tradition by ancient man and compared to tohers storis of creation, not a bad one at all and far closer to the "reality" of it then many other stories of creation.
I don't see how the basic tenets of Christianity fall apart with it or without it.