Do you belong to the U5 mtDNA Haplogroup?

· Scientists used several methods in the late 1990s to establish whether one belongs to the U5 haplogroup and its' various subgroups. Since the classic publication by Richards et al. (2000; see below), DNA sequencing of the "Hypervariable Regions" (HVRs) of mtDNA is the primary method to identify members of U5 and its' subgroups. As described in further detail in links found at this website, DNA is comprised of 4 different nucleotides: "A", "G", "C", and "T". Each DNA strand is comprised of a specific string or pattern of these 4 letters. In the case of mitochondrial DNA (mtDNA), there are regions known as being "hypervariable" -- this means that nucleotides within this region are more likely to mutate to another nucleotide than in the other regions within the mtDNA. The mutations can be used to help define one's mtDNA haplogroup (e.g., U5) and in some cases, to help trace one's ancestry. Again, these mutations are identified by DNA Sequencing in which the entire string of nucleotides within a HVR of mtDNA is identified and compared to a mtDNA reference standard (i.e., the Cambridge Reference Sequence; CRS). For example, Family Tree DNA sequences nucleotides 16001-16454 ("HVR1") and 61-570 ("HVR2"). Differences in nucleotides relative to the CRS are reported as mutations and specific mutations define the various mtDNA haplogroups as shown below. For example, a "16192T" mutation means that the original nucletiode mutated to a "T".

Map Showing Key Mutations That Define mtDNA Haplogroup U5 and Its Subgroups: My interpretation of both Richards et al., 2000, Am. J. Hum. Genet 67:1251-1276, and Helgason et al, 2001, Am. J. Hum. Genet. 68:723-737.

The 16192T mutation is shown by Helgason et al, 2001, Am. J. Hum. Genet. 68:723-737 as defining U5, and is thought to be an unstable nucleotide that often mutates back to "C", especially in the case of U5b and U5a1a. Since 16192T is diagnostic for both U5a and U5a1 and almost non-existent in U5 and U5b, it is shown in the figure below as defining U5a rather than U5 as Helgason et al. (2001) had depicted. Moreover, after looking at the supplementary data for Richards et al. (2000) and even the data in table below, it is unclear why Helgason et al. (2001) claim that 16256T defines U5a as this mutation is not found at all in people belonging to U5a, only U5a1. I will contact the authors to clarify. In the mean time, I show in the figure below that 16256T defines U5a1, not U5a.

Table showing proposed U5 "Founder" haplotypes in Europe and the Near East (as published by Richards et al., 2000, Am. J. Hum. Genet 67:1251-1276).

Haplogroup or Subcluster	Haplotypes Showing Mutations in HVR1, 16050-16495
U5	16270
U5	16270, 16296
U5a	16187, 16192, 16270
U5a1	16093, 16192, 16256, 16270, 16291
U5a1	16189, 16192, 16256, 16270
U5a1	16192, 16256, 16270
U5a1	16192, 16256, 16270, 16291
U5a1	16192, 16256, 16270, 16311
U5a1a	16189, 16256, 16270
U5a1a	16256, 16270
U5a1a	16256, 16270, 16295
U5b	16189, 16270
U5b	16189, 16270, 16311
U5b1	16144, 16189, 16270