Barnyard analysis advice

Question

[cf556]

I have a scRNA dataset with both human and mouse cells. Due to the upstream experiment, there is no way to physically separate the cells by species, nor is there a detectable fluorophore or another modification that could be used to isolate cells from one species or another.

I am wondering if there is a recommended way to identify the species of origin on a cell by cell basis? Would a list of genes that have no ensemble translations across the genomes be a good place to start? Would counts mapped to mouse vs human cells be considered meaningful? Is there an established pipeline for this sort of thing?

Thanks!