On: Student uses black soldier flies to grow pea plant...

[walthamstow]

What's correct there, commas before and after Jack?

[defrost → walthamstow]

Depends very much on the uncle's name and occupation, he may well be an equine veterinarian named Steve.

[sbelskie → walthamstow]

That avoids the worst ambiguity but you still might be helping Uncle Jack murder a horse.

[dotancohen → sbelskie]

Phrased like that, I suppose that the horse would prefer the uncommaed sentence.

[Narishma → sbelskie]

Or you might be helping your uncle Jack by murdering a horse.