each (of them) have vs has

Question

I am wondering if the following sentence is correct.

There are 200 individuals who each have two alleles at single nucleotide site of interest.

In my opinion, have should be changed to has. Is it right?

Here is what I googled related to this. "Some English speakers and writers get confused when using the pronoun phrase “each of” before a plural noun or other pronoun and incorrectly use the plural verb form (“each of them have”). In this case, the correct choice is the singular form of the verb" (https://www.masterclass.com/articles/is-each-singular-or-plural)

Answer 1

The sentence is correct as written, because the subject of the relative clause is the plural pronoun "who". We know that "who" is plural because its referent is "200 individuals". The inclusion of "each" does not change the number of the subject.

The sentence that you quote from Masterclass deals with a different issue: "the pronoun phrase “each of” before a plural noun or other pronoun". In the example given ("each of them have"), the pronoun "each" (which is always singular) is a subject, so its verb must also be singular. That is why it should be corrected to "each of them has".

Your sentence could be re-written to make "each" a subject, and in that case it would, indeed, take a singular verb:

There are 200 individuals, each of whom has two alleles at single nucleotide site of interest.

(By the way, your example sentence seems to have a separate error, since "single nucleotide site of interest" lacks a determiner.)