The story of the family at the center of Roots doesn't really have an explicit ending—after all, the fam is presumably still going strong. (We wouldn't expect anything less form the Kinte fam.)
We watch as they found the town of Henning, Tennessee, setting down roots and becoming one of its most prominent families. There's some sad stuff along the way—like the deaths of Chicken George and Matilda—but it's incredibly joyful to see how far everyone has come.
The real ending is the reveal that Alex Haley, the great-great-great-great grandson of Kunta Kinte, has been narrating the story the whole time. On a literary level, this is a pretty stunning reveal, and an absolute "what the—!" moment. By having this multi-generational, multi-continental story being told by a descendant of its participants, Haley shows that the oral traditions passed down from Kunta to Kizzy have blossomed into something incredible.
What's more, Haley claims to have corroborated these stories with written documents and other oral traditions, helping him find the real people behind his family's stories. He becomes inspired to do this after seeing the Rosetta Stone in a museum, though it takes him a moment to understand that insight.
Take a look:
This key that had unlocked a door into the past fascinated me. I seemed to feel it had some special personal significance, but I couldn't imagine what. (118.3)
While there's some debate over the validity of Haley's genealogical claims (which we discuss in our Symbols analysis of "Faction"), the symbolism of this is crystal clear. Haley's saying that African-Americans have the ability—and perhaps the duty—to look back into their own pasts and take pride in their own familial legacies.
Basically, Haley is saying, "If I can do this, then so can you." That's a powerful statement. It also gets at the heart of why Roots became such a sweeping cultural phenomenon.