On May 10, 2023, researchers released a new high-quality collection of reference human genome sequences that captures substantially more diversity from different human populations than what was previously available. The work was led by the international Human Pangenome Reference Consortium, a group funded by the National Human Genome Research Institute.

The new “pangenome” reference includes genome sequences of 47 people, with the researchers pursuing the goal of increasing that number to 350 by mid-2024. With each person carrying a paired set of chromosomes, the current reference actually includes 94 distinct genome sequences, with a goal of reaching 700 distinct genome sequences by the completion of the project. The work, appearing in the journal Nature, is one of several papers published today by consortium members.

A genome is the set of DNA instructions that helps each living creature develop and function. Genome sequences differ slightly among individuals. In the case of humans, any two peoples’ genomes are, on average, more than 99% identical. The small differences contribute to each person’s uniqueness and can provide insights about their health, helping to diagnose disease, predict outcomes and guide medical treatments.

To understand these genomic differences, scientists create reference human genome sequences for use as a “standard” — a digital amalgamation of human genome sequences that can be used as a comparison to align, assemble and study other human genome sequences.

The original reference human genome sequence is nearly 20 years old and has been regularly updated as technology advances and researchers fix errors and discover more regions of the human genome. However, it is fundamentally limited in its representation of the diversity of the human species, as it consists of genomes from only about 20 people, and most of the reference sequence is from only one person.