Scientists have released the first draft of a genetic blueprint that more accurately reflects the diversity of populations.
The major advance, they say, could usher in a new era of gene-based testing and treatments for everyone, regardless of their ethnic origin.
The current “official” DNA code for humans was published in 2001 as the Human Genome Project and has since been used as the reference against which all other gene sequences are compared.
But the genome was largely based on an anonymous American man of white European descent, creating a bias that likely excluded people of other ancestry from genetic progress.
Now, in a major scientific undertaking, a consortium of scientists has produced a more representative genetic handbook called a “pangenome,” based on samples taken from 47 different individuals.
“This is big science at its best,” said Dr. Karen Miga of UC Santa Cruz.
Seeing “amazing” changes for the first time
“The original Human Genome Project was a landmark achievement,” added Dr Miga.
“It has profound implications for how it transformed scientific discovery and ushered in a powerful era in genetic medicine.
“But we now understand that a single map of the human genome is not an adequate representation of the entire human population.”
Of the 3 billion letters in our genetic code, approximately 99.9% are common to all humans, binding us as a species.
But the 0.1% contains variations that reflect our personal ancestry.
Scientists at the Wellcome Sanger Institute in Cambridgeshire use a gene sequencer during the pandemic file photo: AP
Scientists at the Human Pangenome Reference Consortium analyzed 47 samples and discovered 119 million new genetic code variations and 1,115 repetitive DNA segments containing genes.
The findings were published in the journal Nature.
Professor Evan Eichler of the University of Washington said: “We found more variants than we expected.
“There have been hints of this before, but we don’t have the right ‘microscope’ to see this.
“Now we can see that change for the first time – it’s fantastic.”
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Translating the language of our genes
The consortium aims to decode samples from 350 individuals by the end of 2024, with a particular emphasis on those of African heritage, to reflect our common origins as a species on the continent.
Modern humans did not begin to migrate and disperse around the world until approximately 60,000-90,000 years ago.
The genetic variation found in the pan-genome is very complex.
But they’re really like slightly different translations of a book written in another language.
It is impossible to understand a text without knowing the translation.
Now that the readout of the human genome is more diverse, it should expand the benefits of precision medicine based on an individual’s genetic makeup.
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One example given by the consortium is a variation in the gene for lipoprotein A, a fat molecule in the blood.
It is responsible for the greatest genetic risk associated with coronary heart disease in African Americans.
But these variants were only visible as a result of pan-genome analyses.
New understanding of genetic causes of autism
New perspective could also be used in research, says Prof Eichler autism.
“We couldn’t explain why 70 percent of the kids who came to the clinic had autism,” he said.
“If I can explain to parents why their child has autism and hopefully get better out of it, that’s the holy grail of all of this.
“It’s not just discovering these dynamic regions (with a lot of genetic variation), but it’s life-changing for individuals.”