If you type in Google define anaphora, it gives the following definition (original punctuation and style kept):
the use of a word referring to or replacing a word used earlier in a sentence, to avoid repetition, such as do in I like it and so do they.
Why is there a comma after the word sentence?
Is it correct to italicize "I like it and so do they" in that sentence? Or should it be enclosed in quotation marks? (Perhaps both are correct.)
PS Please do not presume that Google Dictionary is infallible. I've observed plenty of mistakes it has.