41–50 of 63 posts
I had read somewhere that telomere length reduces each time a cell divides. Assuming that, telomere shortening rate is directly indicative of the number of times cells have gone through division. Could that not mean that telomere shortening rate is just estimating cell division rates and the latter relate to life span for an entirely different reason? Is this or some other study show that shortening rate is a better…
this makes me think that telomeres are not the main cause of aging-related death. My mental model is: if you run out of telomere before you get old, you start to get disease - and that’s maladaptive. So there’s evolutionary pressure to slow down your shortening rate, up to a point. Once it becomes unlikely that you’ll outlive your telomeres, there’s no more pressure. So your telomere length + rate becomes a measureme…
> this makes me think that telomeres are not the main cause of aging-related death That's an interesting argument, but couldn't you use the same reasoning to argue that telomeres are the main cause of aging-related death? The mental model I'm thinking is: As you run out of telomeres, you get diseases and you can't reproduce - and that’s maladaptive. So there’s evolutionary pressure to slow down the shortening rate, u…
The shortes mouse telomere is longer than the longest human one
Earlier quoted context omitted.
Humans are double-viviparous species, meaning average grandparent lives past its grandchild's puberty. Humans are also atricial. These traits are shared by elephants, whales and dolphins too. However, humans are the only animal species those are triple-viviparous in occasions, meaning great-grandparent lives past its great-grandchild's puberty.
Human's average lifespans have been a lot shorter throughout history.
Earlier quoted context omitted.
Human's average lifespans have been a lot shorter throughout history.
Average isn't that relevant. It's driven down by early childhood deaths & childbirth deaths (but after a point - menopause - childbirth deaths end).
I had read somewhere that telomere length reduces each time a cell divides. Assuming that, telomere shortening rate is directly indicative of the number of times cells have gone through division. Could that not mean that telomere shortening rate is just estimating cell division rates and the latter relate to life span for an entirely different reason? Is this or some other study show that shortening rate is a better…
Telomeres eventually end, and that's the difference.
If telomere's ending were of significance, then their lengths would be a good predictor of life span. The OP is saying that it's not the length but the shorting rate that counts.
Earlier quoted context omitted.
Average isn't that relevant. It's driven down by early childhood deaths & childbirth deaths (but after a point - menopause - childbirth deaths end).
Infectious disease killed many before old age. Antibiotics are a pretty recent invention.
According to Our World In Data [1] a 20-year-old would expect to live to 60 in 1850 (before penicillin), versus to 80 now.
[1] https://ourworldindata.org/life-expectancy#it-is-not-only-ab...
Earlier quoted context omitted.
Telomeres eventually end, and that's the difference.
It would help if you can explain more. If telomere's ending were of significance, then their lengths would be a good predictor of life span. The OP is saying that it's not the length but the shorting rate that counts.
One of the biggest challenges for studying telomere biology in the context of human aging, is that mice are quite different from humans in terms of their telomere structure. The shortes mouse telomere is longer than the longest human one https://www.ncbi.nlm.nih.gov/pubmed/23956466
http://doi.wiley.com/10.1002/jez.b.20006 Stindl, Reinhard - Is telomere erosion a mechanism of species extinction? (2004)
http://link.springer.com/10.1007/s00114-014-1152-8 Stindl, Reinhard - The telomeric sync model of speciation: species-wide telomere erosion triggers cycles of transposon-mediated genomic rearrangements, which underlie the saltatory appearance of nonadaptive characters (2014)
http://molecularcytogenetics.biomedcentral.com/articles/10.1... Stindl, Reinhard - The paradox of longer sperm telomeres in older men’s testes: a birth-cohort effect caused by transgenerational telomere erosion in the female germline (2016)
more here: http://telomere.at/publications.html
also some old-as-fuck news coverage (2004): https://www.theguardian.com/education/2004/apr/08/science.hi...
https://www.newscientist.com/article/mg18224421.400-chromoso...
oh and, a letter where Stindl outlines the problem in detail: https://www.researchgate.net/profile/Reinhard_Stindl/publica... Stindl, Reinhard - The reanalysis of three large datasets uncovers progressive telomere erosion between healthy human generations and supports an 11-year-old model of telomere-driven macroevolution (2015)
I find it EXTREMELY strange that the OP paper cites NONE of these papers. Like, what the hell?
Earlier quoted context omitted.
Infectious disease killed many before old age. Antibiotics are a pretty recent invention.
Yeah, but the impact isn't that great. According to Our World In Data [1] a 20-year-old would expect to live to 60 in 1850 (before penicillin), versus to 80 now. [1] https://ourworldindata.org/life-expectancy#it-is-not-only-ab...