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  1. If you took a DNA sample from someone's brain and that same persons liver at more or less the same time, would that DNA - all else being equal (e.g. no mutations from radiation) - be exactly the same?

  2. If you took a DNA sample from an embryo, and then that embryo went on to be born, live a long life for 80 years and become an old man/woman; if you were to then take another DNA sample of this person, would that sample be exactly the same as the one which you took when he/she was in the womb? (again, all things being equal - so dismissing mutations due to radiation for example).

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  • $\begingroup$ I don't have much of a scientific background, and am seeking your expertise so that I can consider it's relevance for both the buddhist doctrine of impermanence and christian convictions about souls, personhood, abortion etc. $\endgroup$ – TheIronKnuckle Oct 31 '20 at 13:51
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    $\begingroup$ What do you mean by 'exactly the same'? You should be more specific. You could be talking about the same genes, the same variants, the same heterochromatin configuration, 3-d structure, number of repeats, duplications .... $\endgroup$ – user438383 Nov 20 '20 at 10:14
  • $\begingroup$ In addition to the above, what do you mean by "no mutations from radiation etc"? Do you understand that mutations accumulate due to errors in DNA replication? $\endgroup$ – tyersome Nov 20 '20 at 18:48
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No. even if you exclude the changes in DNA sequences that originate from mismatch errors in DNA replication, mutation etc. Because

1.As a person gets old , the short repeat sequences in the telomere of a chromosome in each cell may be lost or be reduced in amounts leading to a sequence difference.Moreover this changes in telomere sequences may cause cancer/cell apoptosis . Telomere

2.Do not forget transposons (consisted of DNA transposons and retrotransposons). They change their position in genome and multiply their DNA over time.So they also lead to sequence differences in a person(comparing his/her younger and older DNA) Transposons These were the answers to question 2 .You can also think that there might be a slight difference in DNA of two different tissue of the same individual (because of the tolemere and transposons)

As a zygote starts to multiply itself ,slight changes of sequence will happen to the offspring cells .After a dozens of cell division you may encounter a little deviation compared to the original zygote sequence.

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  • $\begingroup$ +1, but it might help to cite the mutation rate, or at the very least something else. An overall sense of the scale of the mutation variation within an organism would improve this answer $\endgroup$ – Punintended Nov 4 '20 at 19:47
  • $\begingroup$ shorter telomeres is one reason dolly died so young, she was cloned from differentiated somatic cells, so she started with shorter telomeres. $\endgroup$ – John Nov 24 '20 at 5:05

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