Reading should be considered a basic ability not hindered much even by average intelligence and being amenable to rote learning. A tangent, but I also wouldn't rule out specific adaptations for reading having been evolved during the last 10k years.

Math is a very specific ability and interest, requiring not just high general intelligence but some additional elusive factor (also likely heritable, as anybody observing "academic dynasties" would note). There is research on this [1] [2], but not nearly enough to say much more.

Anyway, I hope I explained my position on this. It's not the specific gene variants or mechanisms that matter, but basic threshold effects over polygenically heritable traits, and hard diminishing returns on teaching someone who does not meet the talent requirement.

1. https://journals.plos.org/plosbiology/article?id=10.1371/jou... 2. https://pmc.ncbi.nlm.nih.gov/articles/PMC5290743/

Reading is also a bit different in that its everyday utility is blindingly apparent, even to children, which can give strong motivation to learn. My parents have told me that I wanted to learn to read just to know what all of the text I was surrounded with in daily life said, and one of my younger siblings had a strong motive in wanting to better understand and play video games.

Beyond basic arithmetic, the utility of math is not nearly as obvious or widely applicable. It feels much more detached and abstract and this is made worse by popular teaching methods (which frequently lack hands-on examples of the math in question in practical application). It’s only natural that many children, even those who are capable, don’t take interest.

Not an expert in relevant fields by any means, but are you sure that "academic dynasties" are due to genetics and not social factors?