A potential crux:
genetic relatedness is an underlying generator of similarities
I would also say:
niche similarity is an underlying generator of similarities
but I’m not sure you’d admit that, since the niche shows up in the causal graph in at best a cryptic way.
A potential crux:
I would also say:
but I’m not sure you’d admit that, since the niche shows up in the causal graph in at best a cryptic way.