Comment by gwerbret
You should have read the paper (or at least the abstract) first, as they used macaque and human organoid models, too. :) But yes, the overall effects of the region of DNA in question (an enhancer) are fairly small.
The preprint is available here: https://www.biorxiv.org/content/10.1101/2024.04.10.588953v1....
I have read it now. Comment below. As to an increase in mouse neocortical volume—they have ZERO data. Look at their figures 1g and 1h and weep for the crap reviewing.