Study Reveals How Much Genes Contribute to Human Traits

(MENAFN) Researchers have employed cutting-edge whole-genome sequencing to quantify genetic influence on human characteristics—from physical attributes to disease susceptibility—in what scientists describe as a transformative validation of modern genomic methodology. The groundbreaking investigation, published in Nature, analyzed DNA profiles from 347,630 individuals of European ancestry enrolled in the UK Biobank, establishing precise measurements of heritability—the proportion of trait variation attributable to genetic composition rather than environmental forces.

The research partnership uniting Australia's University of Queensland (UQ) with American biotechnology firm Illumina employed direct genetic sequencing technology that captures most genetic variants with unprecedented precision, surpassing capabilities of conventional approaches relying on familial correlation and twin comparisons, according to findings released Thursday.

Whole-genome sequencing circumvents inherent limitations of traditional methodologies by measuring genetic architecture directly in unrelated populations, eliminating confounding environmental variables that inflate family-based estimates, explained Professor Loic Yengo from UQ's Institute for Molecular Bioscience. "An outstanding question in human genetics has been how much twin-based estimates of heritability could be replicated using modern genomic technologies when applied to unrelated individuals," Yengo said, adding the study demonstrates for the first time that this approach works.

Genetic contribution varies dramatically across examined traits
Investigators assessed 34 distinct traits and disease conditions spanning height, body mass index (BMI), cholesterol concentration, and cardiovascular disease vulnerability. Analysis revealed genetic factors account for an average 30 percent of phenotypic variation across populations, though contribution ranges substantially—from 74 percent determinism for height to minimal 12 percent influence on fertility outcomes.

The disparities between sequencing-based findings and conventional estimates underscore methodological limitations in family research, Yengo emphasized. Relatives and twins inherit not only genetic material but also shared domestic and socioeconomic environments, systematically inflating heritability calculations. While family-based investigations attributed 50 percent of BMI variation to genetics, direct genomic sequencing revealed the true genetic contribution at 35 percent—a substantial downward revision challenging previous paradigms.

Disease prevention pathway emerges
Future investigation will concentrate on mapping specific gene variants responsible for disease susceptibility disparities, distinguishing why certain individuals develop conditions while genetically similar counterparts remain protected. This cartography enables prospective early detection and preventive intervention strategies, Yengo concluded.

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