SNP and haplotype variation in the human genome

Area of Science:

• Human Genetics
• Population Genetics
• Molecular Biology

Background:

• Human DNA exhibits significant variability, shaped by evolutionary forces like mutation, genetic drift, gene flow, and natural selection.
• Understanding this variability is crucial for identifying genetic determinants of phenotypic traits and diseases.

Purpose of the Study:

• To survey and summarize key aspects of human DNA variability.
• To investigate how DNA variability differs across genes and human populations.
• To analyze patterns of single nucleotide polymorphism (SNP) and haplotype sharing and linkage disequilibrium (LD) in diverse populations.

Main Methods:

• Sequencing of functional regions in 3950 genes.
• DNA sampling from 82 unrelated individuals across five major ancestral groups: African-Americans, East Asians, Caucasians, Hispanic-Latinos, and Native Americans.
• Analysis of single nucleotide polymorphism (SNP) allele and haplotype sharing, and linkage disequilibrium (LD) in relation to physical distance.

Main Results:

• Significant concordance was observed across different aspects of DNA variability.
• Many genetic variants are common to all studied populations, but a substantial number exhibit restricted distributions.
• Linkage disequilibrium (LD) patterns showed relationships with physical distance, varying across populations.

Conclusions:

• Human DNA variability is a complex interplay of evolutionary processes.
• The distribution of genetic variants is not uniform across human populations.
• Careful consideration of study population is essential when searching for genetic variants associated with phenotypic variation.