But DNA evidence shows that Native Americans are not of Jewish descent.
In order to know if ancient Israelite DNA could be found in the ancient New World, we would have to recognize this DNA. Here we encounter at least two problems. First, most people are probably inclined to think that ancient Israelite DNA should be detectable in current Jewish populations, based on the assumption that the Jews are a race who have remained genetically homogenous since ancient times. The reality, however, is that “Israelite”—like”Jew,””Mormon,” or “American”—is a cultural rather than biological definition. Other than a few extreme examples, current Jewish populations (from whence samples are drawn for Israelite DNA) do not necessarily reflect the DNA make-up of ancient Israelite populations. Second, even anciently the Israelites were composed of multiple genetic backgrounds, each carrying different mtDNA markers from their mothers. By the time Jesus was born, the Jews were an even more genetically diverse group, having intermarried with Canaanites, Babylonians, Persians, Greeks, and Romans, as these outsiders conquered Judah. This intermarriage has only increased to the present day. Under such conditions we should not expect to know what Lehite DNA looked like.
Michael R. Ash, Shaken Faith Syndrome: Strengthening One’s Testimony in the Face of Criticism and Doubt