Post by Admin on May 15, 2020 7:25:58 GMT
The newly sequenced DNA casts a spotlight on an important period in East Asia's early history: the transition from hunter-gathering to agricultural economies.
One hypothesis for population movement in East Asia is that during the Neolithic, a "second layer" of agriculturalists replaced a "first layer" of hunter-gatherers in East and Southeast Asia.
While the genetics of ancient humans in Southeast Asia, Siberia, and the Japanese archipelago have been well-studied, little has been known until now about the genetics of ancient humans in northern and southern China.
Prof. Fu and her team found that these Neolithic humans share the closest genetic relationship to present-day East Asians who belong to this "second layer." This suggests that by 9,500 years ago, the primary ancestries composing the genetic makeup of East Asians today could already be found in mainland East Asia.
While more divergent ancestries can be found in Southeast Asia and the Japanese archipelago, in the Chinese mainland, Neolithic populations already displayed genetic features belonging to present-day East Asians.
Notably, this includes the Early Neolithic southern East Asians dating to ~8,000 years from this study that should have been "first layer" early Asians, according to the earlier hypothesis. In fact, Prof. Fu and her team showed that they shared a closer relationship to present-day "second layer" East Asians. Thus, the results of the current study fail to support a "two layer" dispersal model in Neolithic East Asia in this area.
The scientists also found that Early Neolithic East Asians were more genetically differentiated from each other than present-day East Asians are. In early Neolithic East Asia since 9,500 BP, a northern ancestry existed along the Yellow River and up into the eastern steppes of Siberia, distinct from a southern ancestry that existed along the coast of the southern Chinese mainland and islands in the Taiwan Strait since 8,400 BP.
Population movement may have already started impacting East Asians by the Late Neolithic. For example, the Late Neolithic southern East Asians may have shared a connection to coastal northern East Asians and the former's ancestry may have extended north as well.
Today, most East Asian populations are not clearly separated into two distinct groups. Present-day mainland East Asians from both the north and south share a closer genetic relationship to northern Neolithic East Asians along the Yellow River than to southern Neolithic East Asians on the southern coast of China.
Further analyses show that they are almost all a mixture of northern and southern ancestry from Neolithic East Asia, with northern ancestry playing a larger role. Population movement, particularly from the north along the Yellow River southward was a prominent part of East Asian prehistory after the Neolithic.
Interestingly, present-day Han Chinese in all provinces, north and south, show a similar amount of northern and southern influences.
Southern ancestry, while less represented in mainland East Asia today, had extensive influence on other regions. Present-day Austronesian speakers, who share a close genetic relationship to present-day mainland East Asians but live across a wide swath of islands in Southeast Asia and the Southwest Pacific, show a remarkably close genetic relationship to Neolithic populations from the southern coast of China.
Archaeological materials dating back to the Middle Neolithic have long hinted at the connection between Austronesian islanders and populations in mainland East Asia. Now, the genetic relationships uncovered by Prof. Fu and her team show unambiguous evidence that Austronesian speakers today originated from a proto-Austronesian population that derived from southern China at least 8,400 year ago.
The history revealed by these 26 ancient humans highlights the profound impact that population movement and mixture had on human history, but they also reveal continuity that extends back 9,500 years. Unlike in Europe, influences from Central Asia had no role in the formation of East Asian ancestry, with mixing largely occurring regionally between northern and southern populations in East Asia.
The whole slate of ancestries present across East Asia during the Neolithic is still unknown, as genome-wide data have not been retrieved from many inland regions of mainland East Asia.
But coastal connections between ancient populations in Siberia, Japan, China, and Southeast Asia suggest that as more ancient DNA is retrieved and studied, a complex history of population contact and admixture in East Asian human prehistory will be revealed.
Ancient DNA indicates human population shifts and admixture in northern and southern China
Melinda A. Yang1,2,3, Xuechun Fan4,5, Bo Sun6, Chungyu Chen7, Jianfeng Lang8, Ying-Chin Ko9, Cheng-hwa Tsang10, Hunglin Chiu10, Tianyi Wang1,2,11, Qingchuan Bao12, Xiaohong Wu13, Mateja Hajdinjak14, Albert Min-Shan Ko1, Manyu Ding1,2,15, Peng Cao1,2, Ruowei Yang1,2, Feng Liu1,2, Birgit Nickel13, Qingyan Dai1,2, Xiaotian Feng1,2, Lizhao Zhang1,2, Chengkai Sun16, Chao Ning17, Wen Zeng18, Yongsheng Zhao18, Ming Zhang1,2,15, Xing Gao1,2,15, Yinqiu Cui17, David Reich19,20,21,22, Mark Stoneking14, Qiaomei Fu1,2,15,*
Science 14 May 2020:
eaba0909
DOI: 10.1126/science.aba0909
Abstract
Human genetic history in East Asia is poorly understood. To clarify population relationships, we obtained genome wide data from 26 ancient individuals from northern and southern East Asia spanning 9,500-300 years ago. Genetic differentiation was higher in the past than the present, reflecting a major episode of admixture involving northern East Asian ancestry spreading across southern East Asia after the Neolithic, transforming the genetic ancestry of southern China. Mainland southern East Asian and Taiwan Strait island samples from the Neolithic show clear connections with modern and ancient samples with Austronesian-related ancestry, supporting a southern China origin for proto-Austronesians. Connections among Neolithic coastal groups from Siberia and Japan to Vietnam indicate that migration and gene flow played an important role in the prehistory of coastal Asia.
One hypothesis for population movement in East Asia is that during the Neolithic, a "second layer" of agriculturalists replaced a "first layer" of hunter-gatherers in East and Southeast Asia.
While the genetics of ancient humans in Southeast Asia, Siberia, and the Japanese archipelago have been well-studied, little has been known until now about the genetics of ancient humans in northern and southern China.
Prof. Fu and her team found that these Neolithic humans share the closest genetic relationship to present-day East Asians who belong to this "second layer." This suggests that by 9,500 years ago, the primary ancestries composing the genetic makeup of East Asians today could already be found in mainland East Asia.
While more divergent ancestries can be found in Southeast Asia and the Japanese archipelago, in the Chinese mainland, Neolithic populations already displayed genetic features belonging to present-day East Asians.
Notably, this includes the Early Neolithic southern East Asians dating to ~8,000 years from this study that should have been "first layer" early Asians, according to the earlier hypothesis. In fact, Prof. Fu and her team showed that they shared a closer relationship to present-day "second layer" East Asians. Thus, the results of the current study fail to support a "two layer" dispersal model in Neolithic East Asia in this area.
The scientists also found that Early Neolithic East Asians were more genetically differentiated from each other than present-day East Asians are. In early Neolithic East Asia since 9,500 BP, a northern ancestry existed along the Yellow River and up into the eastern steppes of Siberia, distinct from a southern ancestry that existed along the coast of the southern Chinese mainland and islands in the Taiwan Strait since 8,400 BP.
Population movement may have already started impacting East Asians by the Late Neolithic. For example, the Late Neolithic southern East Asians may have shared a connection to coastal northern East Asians and the former's ancestry may have extended north as well.
Today, most East Asian populations are not clearly separated into two distinct groups. Present-day mainland East Asians from both the north and south share a closer genetic relationship to northern Neolithic East Asians along the Yellow River than to southern Neolithic East Asians on the southern coast of China.
Further analyses show that they are almost all a mixture of northern and southern ancestry from Neolithic East Asia, with northern ancestry playing a larger role. Population movement, particularly from the north along the Yellow River southward was a prominent part of East Asian prehistory after the Neolithic.
Interestingly, present-day Han Chinese in all provinces, north and south, show a similar amount of northern and southern influences.
Southern ancestry, while less represented in mainland East Asia today, had extensive influence on other regions. Present-day Austronesian speakers, who share a close genetic relationship to present-day mainland East Asians but live across a wide swath of islands in Southeast Asia and the Southwest Pacific, show a remarkably close genetic relationship to Neolithic populations from the southern coast of China.
Archaeological materials dating back to the Middle Neolithic have long hinted at the connection between Austronesian islanders and populations in mainland East Asia. Now, the genetic relationships uncovered by Prof. Fu and her team show unambiguous evidence that Austronesian speakers today originated from a proto-Austronesian population that derived from southern China at least 8,400 year ago.
The history revealed by these 26 ancient humans highlights the profound impact that population movement and mixture had on human history, but they also reveal continuity that extends back 9,500 years. Unlike in Europe, influences from Central Asia had no role in the formation of East Asian ancestry, with mixing largely occurring regionally between northern and southern populations in East Asia.
The whole slate of ancestries present across East Asia during the Neolithic is still unknown, as genome-wide data have not been retrieved from many inland regions of mainland East Asia.
But coastal connections between ancient populations in Siberia, Japan, China, and Southeast Asia suggest that as more ancient DNA is retrieved and studied, a complex history of population contact and admixture in East Asian human prehistory will be revealed.
Ancient DNA indicates human population shifts and admixture in northern and southern China
Melinda A. Yang1,2,3, Xuechun Fan4,5, Bo Sun6, Chungyu Chen7, Jianfeng Lang8, Ying-Chin Ko9, Cheng-hwa Tsang10, Hunglin Chiu10, Tianyi Wang1,2,11, Qingchuan Bao12, Xiaohong Wu13, Mateja Hajdinjak14, Albert Min-Shan Ko1, Manyu Ding1,2,15, Peng Cao1,2, Ruowei Yang1,2, Feng Liu1,2, Birgit Nickel13, Qingyan Dai1,2, Xiaotian Feng1,2, Lizhao Zhang1,2, Chengkai Sun16, Chao Ning17, Wen Zeng18, Yongsheng Zhao18, Ming Zhang1,2,15, Xing Gao1,2,15, Yinqiu Cui17, David Reich19,20,21,22, Mark Stoneking14, Qiaomei Fu1,2,15,*
Science 14 May 2020:
eaba0909
DOI: 10.1126/science.aba0909
Abstract
Human genetic history in East Asia is poorly understood. To clarify population relationships, we obtained genome wide data from 26 ancient individuals from northern and southern East Asia spanning 9,500-300 years ago. Genetic differentiation was higher in the past than the present, reflecting a major episode of admixture involving northern East Asian ancestry spreading across southern East Asia after the Neolithic, transforming the genetic ancestry of southern China. Mainland southern East Asian and Taiwan Strait island samples from the Neolithic show clear connections with modern and ancient samples with Austronesian-related ancestry, supporting a southern China origin for proto-Austronesians. Connections among Neolithic coastal groups from Siberia and Japan to Vietnam indicate that migration and gene flow played an important role in the prehistory of coastal Asia.