Post by Admin on May 17, 2020 20:58:49 GMT
Proto-Austronesian origins in southern China and
coastal connections
Austronesian-speaking populations extend from Taiwan to
the Southwest Pacific and to Madagascar. Mainland southern
China has been proposed to be the likely origin of the protoAustronesian
population that entered Taiwan, based on geographic proximity across
the Taiwan Strait and the occurrence of similar artifacts at archaeological
sites from both regions (11, 22, 25, 26). Furthermore, genetic modeling with
mitochondrial DNA (mtDNA) genomes from present-day
Southeast Asians (27) also suggest a southern Chinese origin.
The mtDNA of the 8,320-8,060-year-old Liangdao1 individual
belongs to haplogroup E1, which is common in Austronesianspeaking
populations in Taiwan, the Philippines, and Indonesia today, and
is most similar to mtDNA found in the aboriginal Formosans from Taiwan (28).
Our data also support a proto-Austronesian origin in
mainland southern China. Neolithic southern East Asians
consistently fall on a cline leading to present-day
Austronesians rather than other present-day southern East Asian
populations in a PCA (Fig. 1C), and they share a connection with
present-day Austronesians (Ami) relative to other presentday
southern East Asians, e.g., f4(Mbuti, coastal sEastAsia_EN/LN;
Dai, Ami)>0 (5.2<Z<12.7, table S7A). This connection to present-day
Austronesians extending across all Neolithic samples tested from
mainland southern China and Taiwan Strait islands supports a coastal
southern China origin for proto-Austronesians (29).
We further investigated connections between the ancient
samples and 3,000-year-old Southwest Pacific islanders from
Vanuatu (10), who share a close relationship to present-day
Austronesians. The Neolithic samples from mainland southern China
and the Taiwan Strait islands group with the ancient Vanuatu samples
in a maximum-likelihood tree (b.s. =
82.3-100%, Fig. 2A and fig. S5) and share high genetic similarity
with the Vanuatu in an outgroup f3-analysis (Fig. 1D).
Moreover, a direct f4-comparison demonstrates that Late Neolithic
southern East Asians share a close genetic relationship
with these Austronesian-related Southwest Pacific islanders
(fig. S4A), with no excess connections from either group to
Neolithic northern East Asians (fig. S4B). These results further
support the proposed connection between Neolithic
southern East Asians and proto-Austronesians (29).
A lack of genetic isolation between coastal populations
can be observed all along the coast of East and Southeast
Asia. While most Neolithic Southeast Asians are a mixture of
Hòabìnhian-related and southern East Asian-related ancestry,
a 4,000-year-old population from Vietnam shares an especially
close relationship to coastal Late Neolithic southern
East Asians (table S7B). Strikingly, these coastal connections
extend further north. A 2,700-year-old Jōmon individual from
the Japanese archipelago that separated early from presentday
East Asians was suggested to share genetic affinity to
Hòabìnhians (7), but comparisons including Neolithic East
Asians do not show this pattern (table S8). Instead we find
that the Jōmon individual shows affinities to several coastal
Neolithic populations in Siberia, as well as southern East Asia
(table S9). The patterns demonstrated here show that coastal
regions were areas of interconnectivity and gene flow rather
than isolation. These affinities between populations along the
eastern coast of Asia (and island populations off the coast)
that are not shared by more inland Asian populations suggest
that interactions along marine-related environments played
an important role in the prehistory of coastal Asia.
coastal connections
Austronesian-speaking populations extend from Taiwan to
the Southwest Pacific and to Madagascar. Mainland southern
China has been proposed to be the likely origin of the protoAustronesian
population that entered Taiwan, based on geographic proximity across
the Taiwan Strait and the occurrence of similar artifacts at archaeological
sites from both regions (11, 22, 25, 26). Furthermore, genetic modeling with
mitochondrial DNA (mtDNA) genomes from present-day
Southeast Asians (27) also suggest a southern Chinese origin.
The mtDNA of the 8,320-8,060-year-old Liangdao1 individual
belongs to haplogroup E1, which is common in Austronesianspeaking
populations in Taiwan, the Philippines, and Indonesia today, and
is most similar to mtDNA found in the aboriginal Formosans from Taiwan (28).
Our data also support a proto-Austronesian origin in
mainland southern China. Neolithic southern East Asians
consistently fall on a cline leading to present-day
Austronesians rather than other present-day southern East Asian
populations in a PCA (Fig. 1C), and they share a connection with
present-day Austronesians (Ami) relative to other presentday
southern East Asians, e.g., f4(Mbuti, coastal sEastAsia_EN/LN;
Dai, Ami)>0 (5.2<Z<12.7, table S7A). This connection to present-day
Austronesians extending across all Neolithic samples tested from
mainland southern China and Taiwan Strait islands supports a coastal
southern China origin for proto-Austronesians (29).
We further investigated connections between the ancient
samples and 3,000-year-old Southwest Pacific islanders from
Vanuatu (10), who share a close relationship to present-day
Austronesians. The Neolithic samples from mainland southern China
and the Taiwan Strait islands group with the ancient Vanuatu samples
in a maximum-likelihood tree (b.s. =
82.3-100%, Fig. 2A and fig. S5) and share high genetic similarity
with the Vanuatu in an outgroup f3-analysis (Fig. 1D).
Moreover, a direct f4-comparison demonstrates that Late Neolithic
southern East Asians share a close genetic relationship
with these Austronesian-related Southwest Pacific islanders
(fig. S4A), with no excess connections from either group to
Neolithic northern East Asians (fig. S4B). These results further
support the proposed connection between Neolithic
southern East Asians and proto-Austronesians (29).
A lack of genetic isolation between coastal populations
can be observed all along the coast of East and Southeast
Asia. While most Neolithic Southeast Asians are a mixture of
Hòabìnhian-related and southern East Asian-related ancestry,
a 4,000-year-old population from Vietnam shares an especially
close relationship to coastal Late Neolithic southern
East Asians (table S7B). Strikingly, these coastal connections
extend further north. A 2,700-year-old Jōmon individual from
the Japanese archipelago that separated early from presentday
East Asians was suggested to share genetic affinity to
Hòabìnhians (7), but comparisons including Neolithic East
Asians do not show this pattern (table S8). Instead we find
that the Jōmon individual shows affinities to several coastal
Neolithic populations in Siberia, as well as southern East Asia
(table S9). The patterns demonstrated here show that coastal
regions were areas of interconnectivity and gene flow rather
than isolation. These affinities between populations along the
eastern coast of Asia (and island populations off the coast)
that are not shared by more inland Asian populations suggest
that interactions along marine-related environments played
an important role in the prehistory of coastal Asia.