Ancestry informative markers in indigenous populations from Brazil

Area of Science:

• Population Genetics
• Human Genomics
• Indigenous Studies

Background:

• Brazil's Indigenous population exceeds one million, with significant concentrations in the North and Center-West regions.
• Understanding the genetic heritage of these diverse Indigenous groups is crucial for public health and personalized medicine.
• Previous studies on Indigenous Brazilian genomic ancestry are limited, particularly in the North and Center-West.

Purpose of the Study:

• To investigate the genomic ancestry of Indigenous groups in Brazil's North and Center-West regions.
• To determine the ancestral genetic profile (European, African, Amerindian) using Ancestry Informative Markers (AIMs).
• To assess the utility of AIMs in distinguishing ancestral contributions within these populations.

Main Methods:

• Genomic DNA was extracted from peripheral blood samples of 302 Indigenous individuals from the Tiriyó, Waiampi, Jaguapiru, and Bororó groups.
• Ten Ancestry Informative Markers (AIMs) with a frequency differential >30% between parental populations were selected.
• AIMs were identified using Polymerase Chain Reaction (PCR) to analyze genomic ancestry.

Main Results:

• The Tiriyó group showed Amerindian (AME): 74.1%, European (EUR): 14.7%, and African (AFR): 11.2% ancestry.
• The Waiampi group exhibited AME: 49.3%, EUR: 35.7%, and AFR: 15.0% ancestry.
• The Jaguapiru and Bororó groups displayed AME: 47.1%, EUR: 42.8%, and AFR: 10.2% ancestry.
• AIMs effectively distinguished between African and Indigenous ancestries but showed lower precision for European versus Indigenous ancestry.
• All studied groups predominantly retained their Amerindian ancestral contributions.

Conclusions:

• Indigenous populations in Brazil's North and Center-West have largely maintained their Amerindian genetic heritage.
• Varying degrees of European and African admixture were observed across the studied groups.
• Understanding Indigenous Brazilian genetic profiles is vital for identifying health predispositions and informing inclusive public health policies.