I once before asked this newsgroup about ascorbic acid (vitamin C)synthesis.
Now, I have another question about this subject. Recently, it has been
shown that plants and animals use two very different pathways to make this
molecule. Is there any evolutionary logic to that? If animals just needed
a reducing agent, another might have worked just as well. One could reason
that this particular reducing agent had some binding properties to existing
enzymes. However, in that case, why lose one pathway to make another?