The Origin and Composition of Korean Ethnicity Analyzed by Ancient and Present-Day Genome Sequences

Abstract

Koreans are thought to be an ethnic group of admixed northern and southern subgroups. However, the exact genetic origins of these two remain unclear. In addition, the past admixture is presumed to have taken place on the Korean peninsula, but there is no genomic scale analysis exploring the origin, composition, admixture, or the past migration of Koreans. Here, 88 Korean genomes compared with 91 other present-day populations showed two major genetic components of East Siberia and Southeast Asia. Additional paleogenomic analysis with 115 ancient genomes from Pleistocene hunter-gatherers to Iron Age farmers showed a gradual admixture of Tianyuan (40 ka) and Devil’s gate (8 ka) ancestries throughout East Asia and East Siberia up until the Neolithic era. Afterward, the current genetic foundation of Koreans may have been established through a rapid admixture with ancient Southern Chinese populations associated with Iron Age Cambodians. We speculate that this admixing trend initially occurred mostly outside the Korean peninsula followed by continuous spread and localization in Korea, corresponding to the general admixture trend of East Asia. Over 70% of extant Korean genetic diversity is explained to be derived from such a recent population expansion and admixture from the South.

Do Genes Associated with Dyslexia of Chinese Characters Evolve Neutrally?

“…We examined East Asian populations, expecting if natural selection has acted on genes associated with dyslexia of Chinese characters, the signature would be seen in these populations. At present, publicly available data of these populations were East Asian populations (EAS) in the 1000 Genomes Project phase 3 (1 KG) [ 49 ] and the Korean population from The Personal Genome Project Korea (KPGP) [ 50 , 51 ]. We used them as study populations.…”

Population genomics of East Asian ethnic groups

“…Based on mtDNA, NRY, whole-genome sequencing data and recent ancient DNA data, the common ancestor in EA is characterized as two layers of ancestry: pre-Neolithic hunter-gatherers as the first layer and northern East Asians since Early Neolithic as the second layer [6,18,34]. The two layers of ancestry admixture contribute to the basal genetic architecture of present-day EAs, while subsequent regional migration and admixture introduce additional genetic variations among the EA populations.…”

“…The Korean Peninsula is located to the north of China and its northeast region is bound by Russia. The Korean population has been thought to be highly homogeneous with few admixtures in its history [ 10 , 18 , 19 ]. Previous studies based on mtDNA and Y chromosome show that the Korean ethnic group received a large proportion of genetic components from Northeast Asia and a small proportion from Southeast Asia, which suggests a south-to-north migration route to Korea [ 20 ].…”

“…Similarly, a study based on genome-wide SNP data also supports the male-biased south-to-north migration [ 22 ]. A recent study employing more whole-genome data of both present-day and ancient populations recaptured the two major genetic components from East Siberia and Southeast Asia [ 18 ]. The study also unveiled the origin of the admixed genetic components, which suggests an initial admixture between Tianyuan and Devil’s gate ancestries throughout East Asia and East Siberia until the Neolithic era, followed by a more recent admixture with ancient Southern Chinese populations in the Bronze Age and ultimately a migration to Korea.…”

“…For instance, although with a common ancestor, pairwise F ST between Han Chinese and Japanese and that between Han Chinese and Korean are both greater than that between north and south Hans [ 10 ]. Other population analyses, such as K-mean, STRUCTURE, and principal component analysis (PCA), can also distinguish Han Chinese, Korean, and Japanese as three distinct groups [ 3 , 18 ]. The population structure is mostly related to the different proportions of gene flow sources to these populations.…”