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1000 Genomes Project publishes comprehensive map of genetic variations in Nature journal

October 17, 2017

Richard Gibbs, Ph.D., director of the Human Genome Sequencing Center at the Baylor College of Medicine (one of the project's sequencing centers) said, "What really excites me about this project is the focus on identifying variants in the protein-coding genes that have functional consequences. These will be extremely useful for studies of disease and evolution."

The improved map produced some surprises. For example, the researchers discovered that on average, each person carries between 250 and 300 genetic changes that would cause a gene to stop working normally, and that each person also carried between 50 and 100 genetic variations that had previously been associated with an inherited disease. No human carries a perfect set of genes. Fortunately, because each person carries at least two copies of every gene, individuals likely remain healthy, even while carrying these defective genes, if the second copy works normally.

In addition to looking at variants that are shared between many people, the researchers also investigated in detail the genomes of six people: two mother-father-daughter nuclear families. By finding new variants present in the daughter but not the parents, the team was able to observe the precise rate of mutations in humans, showing that each person has approximately 60 new mutations that are not in either parent.

With the completion of the pilot phase, the 1000 Genomes Project has moved into full-scale studies in which 2,500 samples from 27 populations will be studied over the next two years. Data from the pilot studies and the full-scale project are freely available on the project web site, www.1000genomes.

Researchers studying specific illnesses, such as heart disease or cancer, use maps of genetic variation to help them identify genetic changes that may contribute to the illnesses. Over the last five years, the first generation of such studies (called genome-wide association studies or GWAS) have been based on an earlier map of genetic variation called the HapMap. Built using older technology, HapMap lacks the completeness and detail of the 1000 Genomes Project.

"The 1000 Genomes Project map fills in the gaps between the HapMap landmarks, helping researchers identify all candidate genes in a region associated with a disease," said Lisa Brooks, Ph.D., program director for genetic variation at the National Human Genome Research Institute, a part of the National Institutes of Health. "Once a disease-associated region of the genome is identified, experimental studies must be done to identify which variants, genes, and regulatory elements cause the increased disease risk. With the new map, researchers can just look up all the candidate genes and almost all of the variants in the database, saving them many steps in finding the causes."

Source: Broad Institute of MIT and Harvard