Reddit reviews The Igbos and Israel: An Inter-Cultural Study of the Largest Jewish Diaspora

Aside from the potential for sampling bias and a Simpson's Paradox with immigrants from a given country vs. the average of their native country (like, say Indian immigrants to the US), the Igbo, Lemba, and a few other tribes are Jewish, culturally and/or genetically to some extent. See Y Chromosomes Traveling South: The Cohen Modal Haplotype and the Origins of the Lemba—the “Black Jews of Southern Africa” (2000)

>A previous study using Y-chromosome markers suggested both a Bantu and a Semitic contribution to the Lemba gene pool, a suggestion that is not inconsistent with Lemba oral tradition. To provide a more detailed picture of the Lemba paternal genetic heritage, we analyzed 399 Y chromosomes for six microsatellites and six biallelic markers in six populations (Lemba, Bantu, Yemeni-Hadramaut, Yemeni-Sena, Sephardic Jews, and Ashkenazic Jews). The high resolution afforded by the markers shows that Lemba Y chromosomes are clearly divided into Semitic and Bantu clades.
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>Interestingly, one of the Lemba clans carries, at a very high frequency, a particular Y-chromosome type termed the “Cohen modal haplotype,” which is known to be characteristic of the paternally inherited Jewish priesthood and is thought, more generally, to be a potential signature haplotype of Judaic origin.

Genetics has advanced quite a bit since 2000, but I couldn't find any more recent studies on the matter.

Also see The Igbos and Israel: An Inter-Cultural Study of the Largest Jewish Diaspora.