Re: matrilineal comments

Nathaniel Taylor wrote:

Is there any biological significance to the 'XY' (gender alternating) line, or is this just an exercise?

This is the line from which you get (statistically) more of your X chromosome(s) than any other. A woman gets one X from her mother, representing 50/50 of each maternal grandparent, while she gets the other from the father, but it comes entirely from the paternal grandmother (the paternal grandfather providing the father with his Y- a man gets his sole X exclusively from his mother). Thus, any line with two successive male generations contributes nothing to the X of their descendant, while for all other lines, the percent contribution is divided in half for each female generation, but remains undivided for each male generation. The line with the most male generations, without two in a row, is that which alternates, having twice the contribution per generation as the all-female line.

Curiously, this line differs for siblings of different genders - mine is Isabel, wife of James Baird, b. ca. 1730, or Northampton Co. Pa., my sister's is Joh. Heinrich Kauffer, b. ca. 1730, somewhere in Germany.

taf
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