Back 10 years ago or so there was a lot of DNA misinformation being spread on the web that the X mtDNA haplogroup among Native American proved the Jewish origin myth of Native Americans. At that time, I chased that rumor to ground and found that it was all based on a misinterpretation of a DNA survey of Israel. The X haplogroup was, in fact, identified in that survey. However, it was the X1 haplogroup as contrasting to the Native American X2a haplogroup. And it was found exclusively in a group of people called the Druze, who were immigrants to Israel, and not potential descendents of the Israelites.
I just ran across this interesting article that may relate to the OP:
DNA analysis of residents of Druze villages in Israel
"...Technion researcher Karl Skorecki noted that the findings are consistent with Druze oral tradition suggesting the adherents came from diverse ancestral lineages "stretching back tens of thousands of years." The Druze represent a "genetic sanctuary" or "living relic" that provides a glimpse of the genetic diversity of the Near East in antiquity
The researchers, including Druze co-authors Fuad Basis of the Rambam Medical Center and former Technion student Yarin Hadid, took genetic samples from 311 Druze households in 20 villages in Israel. They soon discovered an unusually high frequency of a mitochondrial DNA haplogroup-a distinct collection of genetic markers - called haplogroup X - among the Druze. Haplogroup X is found at low frequencies throughout the world, and is not confined to a specific geographical region as are most other mitochondrial DNA haplogroups.
Even more unusual, the Druze villages contained a striking range of variations on the X haplogroup. Together, the high frequency and high diversity of the X haplogroup "suggest that this population provides a glimpse into the past genetic landscape of the Near East, at a time when the X haplogroup was more prevalent..."