Friday, November 13, 2009

Playing Favorites

Newsweek has an interesting article about the effect of a grandmother's genes on her grandchildren and how that might influence how dear granny feels about those grandbabies.

It has to do with the X-chromosome, how it's passed down from mama to child, then to grandchild. Can Grandma be more closely related to some of her grandchildren than others? Well, I guess if you play the DNA game, it might appear so. It goes something like this:

  • Paternal grandmother (doesn't apply to me, I don't have a son, but let's see where this leads) - mama passes one of her X's to her son. He then passes his one X to his daughter, his Y to a son. Theoretically, paternal grandma is twice as close to her granddaughter (one of those two X's are hers via son) as to her grandson (nada, since grandma has no Y to contribute). Are you following this?

  • Maternal grandmother (that'd be me) - mama passes one of her X's to her daughter. There's a 50/50 chance grandma's X is the one passed on to either a grandson or granddaughter. Ergo, maternal grandma is related to her grandchildren (sons and daughters) equally.
Hm. So according to this strictly DNA stuff, the daddy's mother will play favorites with her granddaughter, but not with her grandson. The mother's mama will be equally preferential. Did I get that right?

Of course, this is just the science end of things. We grandmas and grandmas-to-be know that loving those grand-chirruns has nothing to do with who gets the most X from whom. It's all about love, love, love.