Is it true you only retain DNA from ancestors 5 generations ago?

[Johan887]

I am curious as I have A.J ancestry on my mom's side and people commonly guess that I, my mother, and my nephews are A.J or to some extent A.J based on their physical appearance. Does this mean an A.J or Hebrew ancestor must've been very recent? I remember my grandfather talking about how his dad/grandfather had a funny accent and it didn't sound English. & my mother admitted my surname means [secret] (I looked up the meaning and it was consistent with the yiddish origin) yet my family is traditionally English. My mom has dark skin, naturally, light brown almost. I asked my mother if the surname was Hebrew or something and she said yes but it seems like she's reluctant about it.

[Graham]

Mate, we share dna with monkeys, bananas and loads of other things. You retain DNA, it becomes diluted, it mutates..

[Johan887]

http://www.isogg.org/wiki/Autosomal_DNA_statistics says you only have to go back 5 generations before the DNA from previous generation (human) ancestors becomes wiped so to speak.

[Johan887]

I suppose, but not enough to affect appearance that much apparently as its insignificant and incomplete blocks of genes

[Johan887]

Other sources seem to say the same thing
Does this mean a white person with a black ancestor 6 generations ago will have no black features?

[calxpal]

5 generations seems to soon to have absolutely 0% DNA, as I have discovered DNA matches with an ancestor in common more than 5 generations back with shared DNA and also genetic links to ancestors further than 5 generations. I'm not expert on this though lol, but I would say more like around 10 generations is when you can be certain you share zero (or near zero) DNA but then one issue is that DNA inheritance is random.

I think DNA would stop being expressed in phenotype fairly sooner than the DNA is washed out though.