In a modest laboratory in Lahore, a genetic revolution is quietly unfolding—one that began with the sequencing of 173,303 Pakistani genomes and has now revealed 34,000 people living without functional copies of at least one gene. These 'human knockouts' are offering an unprecedented window into the true flexibility of the human genome, challenging long-held assumptions rooted in mouse studies and reshaping the future of drug development. For decades, pharmaceutical research has relied heavily on genetically modified mice to identify disease-causing genes and test potential treatments. But as scientists now know, what works in mice often fails in humans—costing billions and delaying cures. This new study, published in Nature, shows why: nearly one in five people in the Pakistan Genome Resource lacks a working copy of at least one gene, including genes previously thought to be essential for life based on mouse models. The discovery that humans can thrive without these genes suggests that our biology is far more adaptable than previously believed.

Led by Dr. Danish Saleheen of Columbia University, the research highlights a critical gap in global genomics: South Asians make up 25% of the world’s population but only 2% of existing genomic data. The Pakistan Genome Resource is not only correcting that imbalance but doing so in a way that accelerates discovery. Because of cultural practices like consanguineous marriage, recessive gene variants are more common, making it easier to identify complete gene knockouts. This makes the database 3.5 times more efficient at finding human knockouts than European-centric biobanks like the UK Biobank. Already, the findings are yielding medical insights: people with non-functional CIDEB genes are protected from fatty liver disease, pointing to a promising new therapeutic target. Meanwhile, the RXFP1 gene, once pursued as a drug target for heart disease based on mouse data, appears to function differently in humans—explaining why past clinical trials failed and saving future research from the same dead end.

What sets this study apart is not just the scale or the genetics, but the ability to follow up. Researchers can re-contact participants, conduct full medical evaluations, and directly observe the effects of gene loss. This real-world validation is rare in genomics and immensely powerful. As Saleheen puts it, 'We simply can't obtain answers to many questions with the more limited European-centric databases.' With two-thirds of human genes still poorly understood, this resource could unlock the function of thousands of genes—and fast-track the development of safer, more effective drugs. In a world where precision medicine is the goal, the path forward may be paved not in mice, but in the diverse genomes of Pakistan.