Were the 12 disciples Jewish?

As was brought up in another question; in so using Matthew 10:1-4, which lists the names of the 12. A response from a contributor stated the unavailability of proof in the Scripture to show that any or all(my own addition to shorten) were truely Jewish or Israelites. The belief I have found, which comes from Jesus's mouth in Matthew 28:19, "make disciples of all nations", leads me to my point. The missing facts that could tell us if the 12 disciples were Jews is irrelevant. It does not matter, that is why it is not found in the Scriptures. We do not need to know, and Jesus already said that He wanted disciples of all nations. Had the information been available stating all to be Jews, then we may find ourselves arguing, as I know I do about things anyway, except this time with Jesus's command, on whether or not a disciple should or should not be either Jewish or of Israelite lineage, or of all nations.