In article <1992May14.205658.18282 at sci.ccny.cuny.edu> dac at sci.ccny.cuny.edu
(David A Cooke) writes:
> I refuse to believe that the prime cause of aging is DNA damage,
>no matter how many times you repeat it, Larry. Until I see some actual
>scientific evidence for that, I think the question of replacing the human
>genome is moot.
Ask and you shall receive.... For all the DNA damage doubters I'd suggest
you go read:
PNAS 1988 85:6465-7, C Richter, J-W Park, BN Ames
Normal oxidative damage to mitochondrial and nuclear DNA is extensive
PNAS 1990 87:4533-7, C Fraga, et al (inc BN Ames)
Oxidative damage to DNA during aging: 8-Hydroxy-2'-deoxyguanosine in
rat organ DNA and urine.
These articles document amounts of DNA damage and its age related increase,
particularly in organs which show some of the greatest cell loss with aging.
I'll give you the 3 main arguments that I find compelling:
1) Ames & co. can measure the damaged DNA bases both in vivo and in the
urine of animals and its increase with age.
2) Albertini and others have documeted the base changes resulting from
DNA damage in several different genes and the increase with age.
3) Cancer rates increase with age^5 and are known to involve mutations
in specific genes. Colon cancer requires mutations within 4 or 5
genes. (Care to figure the probability of mutations in 4 or 5
specific genes only? I cannot convince myself that mutations
happen to tumor suppressor genes or oncogenes and leave other
genes in pristine condition....)