I agree my model is very simplified. (Right now I don't know whether taking a biopsy would or would not age someone, and I'm posting here to find out.)
Interesting point that bigger people don't die that much earlier.
I think the prediction would be that someone who is twice as big as someone else, so an adult who has say 2^45 cells instead of 2^44, would have had one extra division. Naively this would translate to 80 years / 44 divisions = ~ 2 years earlier death.
(Some short men have told me that tall men actually do die early, but when I googled papers to find out just now, that seemed false? Additionally, people with a lot of fat cells seem to die more from cancer (though the main explanation I have heard for this is that fat cells cause inflammation).)
I am quite interested in how (dangers from) cell division are different in the embryonic stage as compared to at a later stage.
Thanks! Point 2. is especially what I am interested to learn about. If there is any place where I can read more about the presence and effect of telomerase on embryos please let me know!
Also, if you have any info on these other potential issues (pathways of aging through cell division) that chat-gpt generated, I am all ears:
a. DNA Damage Accumulation: Every time a cell divides, there is a risk of errors during DNA replication. (Cells do have repair mechanisms that fix most DNA damage, and fortunately they are more capable in young cells.)
b. Mitochondrial Dysfunction: Mitochondria have their own DNA (mtDNA). Mitochondria divide independently of the cell’s nuclear DNA. However, mtDNA is more prone to damage during cell division and replication due to its proximity to reactive oxygen species (ROS) produced during energy generation.
c. Stem Cell Exhaustion: Each stem cell has a limited number of divisions it can undergo before it enters programmed cell death.
I think you shouldn’t count aging in number of days, but rather in the number of cell divisions. (I accept there are other forms of cell damage than just division, but e.g. for telomere length division is quite an important component of aging.)
A newborn baby has fewer than 2^35 cells and an adult has fewer than 2^44 cells. Existing cells are often only replaced after 7 years, so quite a large portion of cell division happens during growth from single cell to adult.
For the sake of argument, assume that a biopsy takes 4 cells out of an 8-cell embryo, then all cells need to divide once more. So that’s 36 (or 45) divisions instead of 35 (or 44).
I was under the impression that cells age when they divide (e.g. telomeres shorten).
If you take a biopsy containing around 6 cells from a 300 cell blastocyst, the remaining cells in the embryo will require more cell divisions to become a normal size person.
Does this mean that taking a biopsy of an embryo ages the resulting person?
Does anyone know of any billionaires who are interested in funding polygenic screening?
My cycle:
First one-two days of period:
A lot of pain, occasionally it makes me vomit, it always makes me unable to do anything
Lots of physical symptoms such as diarrhoea
Super tired (from the pain?) and need to sleep for half the day
I think extremely slowly during this time
I think the best description of this state is that I’m ill
Last two-three days of period:
Quite neutral state of being
First two weeks after period:
Mentally calm
More able to concentrate
This is the best time for boring but important work
Third and fourth week after period:
[These effects slowly get more and peak in the second week]
Emotionally more fluctuating, more ecstatic, more crying, more anger, higher libido
Cognitively I’m sharpest during this time (I can think the fastest but can’t focus that well)
This time probably comes closest to mania for me
Pain control:
I’ve tried taking paracetamol during my period, but it doesn’t affect the pain at all.
I now use feminax (have been using it for a couple of years), and it does reduce the pain, but no other symptoms, e.g. I still need to sleep a lot and still feel ill.
To mitigate the pain I also take a lot of hot baths and use hot water bottles
Pain as a symptom:
I’ve never gotten myself tested for endometriosis, but it doesn’t seem unlikely to me that that’s what causes the severe pain. The main symptom for endometriosis is painful periods. One in ten women are suspected to have it, but it’s very underdiagnosed. Maybe that’s because GP’s don’t take the pain seriously? I asked my GP about pain control and he suggested I go on the pill, and did not even mention endometriosis.
I wasn't aware! That's great!
Shower thought: How much are new posts evaluated based on authors’ old reputation?
We could find out if all posts were anonymous for a duration of x weeks and posts could only be upvoted during that time. [If it’s considered important that posts can be upvoted later as well, then there could be a second karma tally for the non-anonymous period after the anonymous one.]
If authors’ posts get a similar number of upvotes compared to when their names were public, then that’s a sign that every post is evaluated independently.
Whether it’s good or bad to evaluate posts based on the author is unclear imo:
- good, because it’s a quick style filter, e.g.... (read more)
New information I came across is:
A blastocyst has an outer layer of cells (trophectoderm) and an inner mass. The trophectoderm is what becomes the placenta and the inner mass becomes the baby. The biopsy is taken from the trophectoderm.
So if anything, it sounds like the biopsy would "age the placenta" not the baby.