The idea of a genetic "line" is not the concept people think it is.
Humans already share 99% of their DNA. Of the 1% that creates our differences, after 5 to 7 generations, depending on how you look at it, the similarity of your descendent's DNA to your DNA would essentially be indistinguishable from noise or random variance in people who you aren't even related to at all.
Talk of lines and blood and bloodlines has more to do with people really wanting to not disappear into oblivion.
Comments
The idea of a genetic "line" is not the concept people think it is.
Humans already share 99% of their DNA. Of the 1% that creates our differences, after 5 to 7 generations, depending on how you look at it, the similarity of your descendent's DNA to your DNA would essentially be indistinguishable from noise or random variance in people who you aren't even related to at all.
Talk of lines and blood and bloodlines has more to do with people really wanting to not disappear into oblivion.