Jews are descendents of the Judeans (tribes of yehuda and binyamin out of the 12 tribes). Also they had many converts, as judaism allows for conversion, through the ages, some canaanites are an example.
Talmud and rabinnic interpretations and laws came to power after the roman exile and even after the first babylonian exile (the destruction of the first temple) as the babylonians exiled the judeans to babylon (specifically the "ellites").