Rambam, Introduction to the Mishnah 22 הקדמת הרמב״ם למשנה כ״ב

The third [appendix] relates to when it is made known about the lineage of the sages of the Mishnah. Among them are [that] Rabban Gamliel is the son of Rabbi Yehudah HaNassi and Rabbi Yehudah HaNassi is the son of Rabban Gamliel the son of Rabban Shimon ben Gamliel the Elder, [Gamliel the elder being] the son of Rabban Shimon ben Hillel HaNassi. And [that Hillel] is Hillel the Babylonian upon which a group of the later sages relied upon and [went] according to his opinion. And [this group] was called the House of Hillel.

And this Hillel is from the [descendants] of Sheftiah the son of Avital the son of David. And [about] these seven sages it has already been made clear that they are from the seed of David.

And among them are four that are from the congregation of converts. And they are Shemayah and Avtalyon and Rabbi Akiva and Rabbi Meir.

And among them are priests: Shimon the Righteous, to whom all the laws go back, to fulfill that which is stated (Deuteronomy 33:10), "They shall teach Your laws to Yaakov"; and Rabbi Elazar ben Azariah is also tenth [generation in the line] of Ezra; and Shimon his uncle, and he is known [as] Shimon the brother of Azariah; and Rabbi Elazar ben Shamua; and Rabbi Chaninah the Deputy of the priests; and Rabbi Shimon his son, and he is known [as] Rabbi Shimon the Deputy; and Yishmael ben Pavi; and Yochanan the High Priest and Rabban Yochanan ben Zakkai; and Yose ben Yoezer; and Rabbi Yose the Priest; and Rabbi Tarfon; Rabbi Elehoeinai ben HaKof, Chanme'el the Egyptian.

And the rest of them are from Israel and no lineage about them that I know about is known.