NewBromance t1_irppgvo wrote on October 10, 2022 at 2:16 AM

Reply to comment by iayork in How evolution get rid of unnecessary stuff? by CoolAppz

Where does humans inability to make vitamin C fit into all this? I know we get vitamin C from our diet so it rarely becomes a problem unless you're on a ship or low food quality environment - and then scurvy happens. So there was no selective pressure to keep it working really, but was there a selective pressure to stop it working like point 2.

I.e. do animals rhat can synthesis vitamin C have to pay "an upkeep" to maintain the bodies ability to do so or something?

konwiddak t1_is1fubu wrote on October 12, 2022 at 4:37 PM

I don't believe we think there was a selective pressure to get rid of it. However mutations and differences don't necessarily happen in isolation - it could have been that the ape who had the original mutation might have happened to be exceptionally strong/smart/fertile (or plain "lucky") and therefore it was advantageous for his genes to propagate despite the flaw.

NewBromance t1_is1g673 wrote on October 12, 2022 at 4:40 PM

Almost like the gene piggybacked of another gene.

Ape has a gene that means he can't make vitamin C, but that doesn't matter because he gets it all from his diet. However he also has a bunch of useful genes that make him more successful and so him and his descendents do very well and thr defective vitamin C gene goes along for the ride?

konwiddak t1_is1vwfb wrote on October 12, 2022 at 6:22 PM

Pretty much, the vitamin C gene could have been completely unconnected to the success of this genetic lineage. We don't really know, this is just a theory - it could have also been that there was a forest fire and only one family of apes survived.