Allele frequencies of the ABCC11 gene for earwax phenotypes among ancient populations of Hokkaido, Japan

Abstract

Human earwax is classified into wet and dry types, which are determined by a single-nucleotide polymorphism in the adenosine triphosphate-binding cassette, sub-family C11 (ABCC11) gene locus. To investigate the allele frequencies of the ABCC11 locus within ancient populations on the Northern Japanese island of Hokkaido, amplified product-length polymorphisms were analyzed for 50 specimens of the Okhotsk people and 35 specimens of the Jomon and Epi-Jomon people excavated from various archaeological sites of Hokkaido. Of these specimens, 31 Okhotsk and 19 Jomon/Epi-Jomon samples were genotyped successfully. Frequencies of the wet-type allele in the Jomon/Epi-Jomon people, considered a major ancestor of the Ainu, were higher than those of other Northeastern Asian populations, including the modern Ainu. By contrast, in the Okhotsk people, believed to originate from East Siberia, frequencies of the dry-type allele were relatively higher than those in the Ainu and Jomon/Epi-Jomon people. These results suggest that gene flow from the Northeastern Asian Continent to descendants of the Jomon/Epi-Jomon people of Hokkaido through the Okhotsk people occurred, resulting in the establishment of the Ainu.

Polymorphisms and allele frequencies of the ABO blood group gene among the Jomon, Epi-Jomon and Okhotsk people in Hokkaido, northern Japan, revealed by ancient DNA analysis

“…In addition, allele frequencies of the earwax gene ABCC11 in those people were significantly different from each other. 33 These findings strongly show that Jomon/Epi-Jomon and Okhotsk people have characteristics that are different from each other in mitochondrial (maternal) and autosomal (biparental) gene pools, in addition to the classical morphological differences.…”

“…Although the Ainu (modern indigenous people in Hokkaido) could have been established by genetic mixtures between direct descendants of the Neolithic Jomon and Okhotsk people, [31][32][33] gene flow from the Okhotsk people to the Ainu was not tested in this study because the previous data of the ABO blood group for the Ainu are of an immunological nature and show only frequencies of the A, B and O groups; that is, frequencies of subtypes of the A, B and O groups for the Ainu are not available. To further understand the history of populations in Hokkaido, it is important to clarify the polymorphisms of the ABO blood group gene in the Ainu for comparison with those of the Jomon/Epi-Jomon and Okhotsk people.…”

“…[31][32][33][34] To avoid surface contamination of external DNA, each bone or tooth was soaked in sodium hypochlorite solution (Nacalai Tesque, Kyoto, Japan) for 5 min, rinsed with DNase-/RNase-free distilled water and air-dried. Samples were then powdered with a standard dental drill.…”

“…By contrast, Sato et al 31,32 demonstrated that mtDNA haplogroups Y, G1b and N9b were major in the Okhotsk people and that they were genetically closely related to modern local populations in Sakhalin and lower regions of the Amur River, including the Ulchi, Nivkhi and Negidal. Moreover, Sato et al 33 revealed that allele frequencies of the ABCC11 gene, which is an autosomal gene associated with earwax phenotypes (wet/dry), were significantly different between the Jomon/Epi-Jomon and Okhotsk people. The Jomon people had a relatively higher frequency of the wet allele, showing genetic characteristics similar to those of the Ainu.…”

Genotype frequencies of the ABCC11 gene in 2000-3000-year-old human bones from the Epi-Jomon and Jomon sites in Hokkaido, Japan

“…For autosomal DNA of the Jomon/Epi-Jomon and Okhotsk people, Sato et al (2009b) analyzed allele frequencies of the ABCC11 gene, and reported that the frequencies of recessive allele A increased in the order Jomon, Ainu and Okhotsk. In addition, they suggested that gene flow occurred from the Okhotsk people to the Jomon lineage; however, Sato et al (2009b) succeeded in analyzing only one EpiJomon specimen, and information on the ABCC11 gene alleles of the Epi-Jomon people is still lacking.…”