Punctuation commas

Scientist have mapped the human genome. They learn more every day about how genes affect an individual's health.
My answer
Scientist have mapped the human genome, so they learn more every day about how genes affect and individual's health.

I guess "so" works OK here, but I'd be inclined to use "and" -- your comma placement is correct.

Thank you

Your answer is correct, but let me explain the use of punctuation commas in the sentence.

Punctuation commas are used to separate items in a sentence and help to clarify the meaning. In the given sentence, a punctuation comma is needed to connect the two independent clauses: "Scientist have mapped the human genome" and "they learn more every day about how genes affect an individual's health."

Therefore, the correct sentence would be:

"Scientists have mapped the human genome, so they learn more every day about how genes affect an individual's health."