HLA polymorphism in six ethnic groups from Pakistan

Area of Science:

• Population genetics
• Human leukocyte antigen (HLA) system
• Molecular anthropology

Background:

• The human leukocyte antigen (HLA) system exhibits extreme polymorphism, making it a valuable tool for population genetic studies.
• Understanding genetic diversity within and between ethnic groups is crucial for anthropological and medical research.

Purpose of the Study:

• To investigate the genetic polymorphism of six Pakistani ethnic groups at key HLA loci.
• To analyze allele and haplotype distributions to understand population structure and relationships.
• To compare Pakistani populations with global groups and infer historical admixture events.

Main Methods:

• Utilized polymerase chain reaction with sequence-specific primers (PCR-SSP) to analyze HLA-A, -B, -C, -DRB1, and -DQB1 loci.
• Calculated allele and three-locus haplotype frequencies for Baloch, Brahui, Sindhi, Burusho, Kalash, and Pathan populations.
• Employed phylogenetic tree and correspondence analysis for population comparisons.

Main Results:

• Significant variation in HLA allele and haplotype distributions was observed among the six Pakistani ethnic groups.
• The Kalash population was found to be genetically distinct from other Pakistani groups studied.
• The Baloch and Brahui showed close genetic relatedness, while Sindhi populations indicated admixture with northern groups.
• Phylogenetic analyses placed Pakistani ethnic groups within the broader cluster of Asian Indian populations.
• Observed three-locus haplotypes suggest historical admixture with Caucasian and Oriental populations.

Conclusions:

• HLA genetic data reveals unique population structures within Pakistan, with the Kalash being an outlier.
• Evidence of admixture between northern and southern Pakistani populations was identified.
• Pakistani ethnic groups share genetic affinities with Asian Indian populations, with historical influences from Caucasian and Oriental groups.