Is there a "mom gene"?

In Charlotte Perkins Gilman's story, "The Unnatural Mother," she writes about a woman who, from her home on the edge of town, observed a dam about to break, which would have the power to sweep away 3 villages in its wake.  So this woman ran full-force from her home down to the town, delivered the news, and the lives of the residents of all 3 villages were saved.  Immediately upon delivering the news she ran back to her own home to retrieve her only child who was asleep in her crib. Just as the woman reached the gate of the house, the tidal wave swept her away, it knocked the house off its foundation and it came to rest a distance away.  The child was found inside, alive.  The mother, who saved the lives of all the residents of 3 villages, died.  In town folklore, this woman should be observed as a hero.  Instead, the story is told that she risked the life of her own child in order to save the lives of others.  The reality that - had the mother stopped to grab her child, lugging her with her - all would have been lost for everyone.   Exemplified by the remark, "A mother's duty is to her own child! She neglected her own to look after other folks' -- She was such an unnatural mother!"

Although this story is myopic in scope, it begs the question, what does "maternal instinct" mean?  Is there a "maternal gene"?  Richard Dawkins wrote of "the selfish gene" (a biological view of genes that ensure survival as well as ensuring that these genes are passed on).  He writes that power struggles between the host (a person) and its genes is rare; only when an organism understands its own interests as distinct from those of its genes can there be true conflict. there a "mom gene?" 

On the Katie Couric show, this question was asked of Dr. Amy Blackstone, Chair of Sociology at the University of Maine.  In this short clip, you'll hear some interesting facts as well as the voice of a woman who states adamantly that she has never felt a maternal urge.

Note: after time goes by the links to network clips are disabled--instead, you can see a summary of Dr. Blackstone's interview here: