2023-05-16 12:15:46
An international team of scientists has publicly released a new, high-quality collection of reference human genomic sequences that captures a substantially greater diversity of different human populations than previously available. The work has been led by the International Human Pangenome Reference Consortium, a group promoted by the National Human Genome Research Institute (NHGRI), one of the US National Institutes of Health.
The new reference human pangenome includes genomic sequences from 47 people, and the researchers are aiming to increase that number to 350 by mid-2024.
A genome is the DNA instruction set that helps every living thing develop and function. Genomic sequences differ slightly between individuals. In the case of humans, the genomes of any two people are more than 99% identical. Small differences contribute to the uniqueness of each person and can provide information about their health, helping to diagnose diseases, predict results and guide medical treatments.
To better understand these genomic differences, scientists create reference human genomic sequences to use as “standards,” that is, as a digital amalgamation of human genomic sequences that can be used as a comparison to align, assemble, and study other human genomic sequences.
The original reference sequence of the human genome is almost 20 years old and has been regularly updated as technology has advanced and researchers have corrected errors and discovered more regions of the human genome. However, its representation of the diversity of the human species is fundamentally limited, as it consists of the genomes of only about 20 people, and most of the reference sequence comes from a single person.
“Each person has a unique genome for them, so using a single reference genomic sequence for all people can lead to inequities in genomic analyses,” said NHGRI’s Adam Phillippy, a member of the team that prepared the new version. of the human pangenome. “For example, predicting a genetic disease might not work as well for someone whose genome differs more than usual from the reference genome.”
The new version of the reference human pangenome encompasses more genetic details of the human population than ever before, and will greatly aid medical research of all kinds. (Illustration: Darryl Leja / National Human Genome Research Institute / NIH. CC BY)
The reference human pangenome that has been used recently has gaps that reflect the lack of information, especially in areas that were repetitive and difficult to read. Recent technological advances, such as long-read DNA sequencing, which reads longer stretches of DNA at a time, have helped researchers fill in those gaps.
Using advanced computational techniques to align the various genome sequences, the researchers built the new reference human pangenome. It is also based on the previous reference genomic sequence, but by adding more than 100 million new bases, or “letters” in the DNA.
Whereas the previous reference genome sequence was single and linear, the new pangenome represents many different versions of the human genome sequence at the same time. This offers researchers a broader range of options for using the pangenome in the analysis of other sequences in the human genome.
“The reference human pangenome will allow us to represent tens of thousands of novel genomic variants in regions of the genome that were previously inaccessible,” says Wen-Wei Liao, from Yale University in the United States and a member of the team that has prepared the new version of the pangenome. reference human pangenome. With this new version, as Liao points out, biomedical research can be accelerated, increasing knowledge about the relationship between gene alterations and health disorders.
The presentation of the new version of the reference human pangenome has been made through the academic journal Nature, under the title “A draft human pangenome reference”. (Fountain: NCYT de Amazings)
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