> In October 2015, two independent studies showed that elephants have 20 copies of tumor suppressor gene TP53 in their genome, where humans and other mammals have only one.[17] Additional research showed 14 copies of the gene present in the DNA of preserved mammoths, but only one copy of the gene in the DNA of manatees and hyraxes, the elephant's closest living relatives.[18] The results suggest an evolutionary relationship between animal size and tumor suppression, as Peto had theorized.
Is it possible that the evolutionary relationship arises from the size relationship? Basically: if elephants' ancestors grew in size and started dying much more quickly and commonly from cancer, nature would select for individuals who just so happened (via their increased risk of mutation) to have more copies of genes like TP53.
> The results suggest an evolutionary relationship between animal size and tumor suppression
My napkin formula would be p_tumor_body=(V_body/V_cell)*p_tumor_cell, so your statment makes intuitive sense, I'd say. The more cells you have, the more tumor suppression you need to make it a secondary cause of death over your expected life span.
I shouldn't comment on HN from bed after an evening out. Of course the rule of proportion is the wrong approach here. Even though the dimensional analysis seems to work out, it's still wrong. Bad case of thoroughly addled brain, this is supremely embarassing, and too late to delete now. I should be able to do this in my sleep, but I clearly wasn't. Seems there's not enough probabilities in my day-to-day, I will make a point of adding a few to fix my intuitions.
Is it possible that the evolutionary relationship arises from the size relationship? Basically: if elephants' ancestors grew in size and started dying much more quickly and commonly from cancer, nature would select for individuals who just so happened (via their increased risk of mutation) to have more copies of genes like TP53.