Abstract
Previous studies in population genetics have proposed that the Y-chromosomal (Y-DNA) haplogroup D ancestor likely originated from Africa. The haplogroup D branch next started Out-of-Africa migration, rapidly expanded across Eurasia, and later diversified in East Asia. Y-DNA haplogroup D-M55, one of the branches of haplogroup D, is only found in modern Japanese males, suggesting that individuals with Y-DNA haplogroup D migrated from the Eurasian continent. Based on previous observations, Y-DNA haplogroup D is expected to be associated with some male characteristics including personality. Therefore, this study investigated whether the Y-DNA haplogroup D-M55 is associated with several physiological and psychological characteristics, including exploratory motivation and human relationship-related perception. We recruited Japanese young adult males and females and investigated the association between Y-DNA haplogroup D-M55, physiological [body mass index (BMI)], and several psychological parameters [perceived number of close friends, behavioral inhibition system/behavioral activation system (BIS/BAS), perceived happiness, and perceived loneliness]. The results indicated that males with haplogroup D-M55 had a higher BMI and more close friends, compared with non-carrier males. Additional multiple regression analyses, which tested the hypothesis that haplogroup D-M55 predicts BMI and perceived number of close friends, confirmed our hypothesis, even after controlling for the potentially confounding variables of age and sex. We also analyzed the gene–gene interaction between haplogroup D-M55 and an autosomal gene polymorphism associated with BMI and human relationships, such as the dopamine D2 receptor gene (DRD2: rs1800497). Results showed gene–gene interactions between haplogroups D-M55 and DRD2 in BMI. Based on these findings, it is demonstrated that Y-DNA haplogroup D is associated with human personality.
Highlights
We inherit half of our DNA from our father and half from our mother
There were no significant differences in age and Behavioral Activation System scale (BAS)
We investigated the association between haplogroup D-M55 and several physiological and psychological parameters, including body mass index (BMI), number of close friends, behavioral inhibition system/behavioral activation system (BIS/BAS), subjective happiness, and loneliness
Summary
We inherit half of our DNA from our father and half from our mother. Genetic modification occurs frequently when DNA is transmitted from parents, and even siblings with the same parents have different DNA. There are some instances in which the DNA of the parent is inherited with little change. These are maternal mitochondrial DNA and paternal Y-chromosomal DNA (Y-DNA). Because both mitochondrial DNA and Y-DNA change little by little due to mutations, we can assume the order in which the existing mutations were separated from their common ancestor. Previous studies have proposed that the Y-DNA haplogroup D ancestor likely lived in Africa around 50,000–70,000 years ago and that the haplogroup D branch (haplogroup D1-M174) started Out-of-Africa migration and rapidly expanded across Eurasia, later diversifying in East Asia (Haber et al, 2019; Hallast et al, 2021). In Japan, haplogroup D-M55 (haplogroup D1a2a: one of two branches of haplogroup D1a) is found in approximately 33% of modern Japanese males (Sato et al, 2014)
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