Polynesian mitochondrial DNAs reveal three deep maternal lineage clusters

Area of Science:

• Human Population Genetics
• Mitochondrial DNA Analysis
• Oceanic Migration

Background:

• Polynesians are traditionally viewed as a unified cultural and linguistic group.
• Previous genetic studies have explored the expansion into Remote Oceania.
• Understanding maternal lineages is key to tracing ancient migrations.

Purpose of the Study:

• To investigate the maternal genetic diversity within Polynesian populations.
• To identify distinct mitochondrial DNA (mtDNA) lineages and their origins.
• To re-evaluate the genetic history of Polynesian expansion.

Main Methods:

• Mitochondrial DNA (mtDNA) region V deletion marker analysis using PCR.
• Sequencing of mtDNA hypervariable control regions.
• Comparative sequence analysis across diverse populations.

Main Results:

• Discovery of at least three distinct mtDNA lineage groups in Polynesians.
• Identification of deep maternal ancestral connections predating 85,000 years.
• Significant sequence divergence between mtDNA groups, particularly those with and without the region V deletion.
• Group I lineages, common in Remote Oceania, show mixed Asian and potentially Native American/Indonesian affinities.
• Group II lineages may represent Papuan Melanesian maternal ancestry.
• Group III lineages suggest a link between Samoa and Indonesia.

Conclusions:

• Polynesian maternal genetic heritage is more complex than previously assumed, originating from at least two distinct geographic sources.
• Ancient Polynesian populations likely resulted from admixture between mainland Asian immigrants and established Melanesian populations.
• The colonization of Remote Oceania involved the transmission of diverse maternal genotypes across the Pacific.