Hi Guys. Let’s look at the Gulo gene for a moment. The GULO gene is or was responsible for vitamin C production. It has now been damaged by mutation and is no longer functional in man and in most critters. Imagine this defect appearing and becoming the norm in a primitive population that doesn’t understand vitamins and genetics. We can imagine that scurvy would begin to appear and they would have no idea what to do about it, that is unless there was some compensation.
Maybe there was. Here is Gen 9:3.
//Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things.//
Before the deluge mankind ate plants but immediately after the flood God gave man the animals as well. It’s a puzzling thing. It’s described in a matter of fact way and no explanation is given as to why.
Here is perhaps why. Eating meat compensates for a lack of vitamin C. Meat does contain vitamin C but more importantly it has other anti scurvy properties. Also a lower carb diet makes what vitamin C is available more easily absorbed.
So the likely scenario is that the GULO defect was a late preflood mutation. Before the flood most people probably had a functional GULO gene. We can assume that Noah had the defect and so everyone descended from him also had it. We could have easily became extinct if the Lord hadn’t adjusted our diet accordingly.