Where did my grandmother's X chromosome go?

[Héloïse]

Hello, I'm sorry I'm posting my question here, but I have no idea where the questions on the X chromosome lie.


I was just wondering how it was possible that I would not share any segment of the X chromosome with my grandmother? It's usual ? Yet I share 20% of my DNA with her, but nothing in the X chromosome, it seemed weird.

If you have an explanation for me, I searched but I can not find anything.

Thank you so much !

[td120]

I would guess it was your mother's mother you had in mind ,correct?
It happens that the daughter can inherit nothing of her maternal grandmother's X chromosome. It is somehow rare,yes-like in this graphic:



http://smithplanet.com/stuff/x-chromosome.htm

[MOESAN]

td20: seems sensible explanation - the O re-combination could seems weird, but who knows? - All the way, it's very possible that the most of the X chromosome genes of the maternal grand'mother were lost, as you explain. Let's not confuse X transmission with mt transmission.