REAGENT or RESOURCE	SOURCE	IDENTIFIER
Biological samples
Sinhala	Field Collection from Śrī Laṅkā	See Figures 2 and 3 for population names
Śrī Laṅkā Tamils (STS)	Field Collection from Śrī Laṅkā	See Figures 2 and 3 for population names
Śrī Laṅkā Tamils (UK)	1000 genomes (http://ftp.1000genomes.ebi.ac.uk/vol1/ftp/)	See Figures 2 and 3 for population names
World population data	Pathak et al.42	See Figures 2 and 3 for population names
Chemicals, peptides, and recombinant proteins
Agarose	MERCK	Cat# A9539
Tris EDTA Buffer, Molecular Biology Grade	Fisher Scientific	Cat# AAJ75893AP
Critical commercial assays
DNA extraction Kit	Qiagen	Cat# 51104
MinElute PCR Purification Kit	Qiagen	Cat# 28006
Illumina-Infinium Global Screening Array	1.0 (GSA-24v1-0)	Cat# 20031669
Deposited data
The Genotype data of Sinhala	This study	https://doi.org/10.6084/m9.figshare.23975601
The Genotype data of Śrī Laṅkā Tamil	This study	https://doi.org/10.6084/m9.figshare.23975601
Software and algorithms
PLINK v1.9	Chang et al.44	https://www.cog-genomics.org/plink/1.9/
EIGENSOFT v6.1.4	Patterson et al.45	https://github.com/DReichLab/EIG
ADMIXTURE	Alexander et al.46	https://dalexander.github.io/admixture/
ADMIXTOOL	Patterson et al.47	https://github.com/DReichLab/AdmixTools
BEAGLE 5.4	Browning et al.48	http://www.gnu.org/licenses/
fineStructure	Lawson et al.49	https://people.maths.bris.ac.uk/∼madjl/finestructure/fs-2.1.3.tar.gz
MEGA-X	Kumar et al.50	https://www.megasoftware.net/show_eua
ChromoPainter	Lawson et al.49	https://people.maths.bris.ac.uk/∼madjl/finestructure/fs-2.1.3.tar.gz
ALDER	Loh et al.51	http://cb.csail.mit.edu/cb/alder/alder_v1.03.tar.gz
runs of homozygosity (RoH)	Chang et al.44	https://www.cog-genomics.org/plink/1.9/
merged IBD	Browning & Browning52	http://www.gnu.org/licenses/
Refined IBD	Browning & Browning52	http://www.gnu.org/licenses
mt-DNA nomenclature	Van Oven & Kayser53	Phylotree.org