Answer:
The 12 gates are named after the 12 Apostles of Christ, the 12 foundations represent the original 12 Tribes of Israel. The foundation represents the Old Testament and are as follows: Reuben, Simeon, Levi, Judah, Dan, Nawphtali, Gad, Asher, Issachar, Zebulun, Joseph and Benjamin.
The gates with the 12 Apostles represent the New Testament built by the 12 Apostles after the acention of Jesus Christ, and are as follows: Simon Peter, Jmes, John, Andrew, Philip, Thomas, Bartholomen, Matthew, James (of A), Simon Zelotes, Judas (of J) and Judas Iscariot. *
*Listed in Acts:1:13.