NEW YORK (GenomeWeb) – A team from Australia has started to put together the largest collection of whole-genome sequences from thousands of healthy, elderly individuals to date.
Researchers from the Garvan Institute of Medical Research, the University of New South Wales, and Monash University described the strategy behind this resource — called the Medical Genome Reference Bank (MGRB) — in a paper published online today in the European Journal of Human Genetics.
"The Medical Genome Reference Bank can tell us much about what it means to grow old but remain well, and is a powerful tool to help us deconstruct the genetics of common diseases," co-senior author David Thomas, a researcher affiliated with the Garvan Institute of Medical Research and the University of New South Wales, said in a statement.
Since the MGRB program was launched in 2012, he and his colleagues have used Illumina instruments and blood sample-derived DNA to generate at least 30-fold average genome coverage for some 4,000 individuals who have reached the age of at least 70 years old without diagnoses such as cancer, cardiovascular disease, or dementia. Roughly 3,000 of those have been analyzed so far, and the rest of the analyses are expected to wrap up by the end of next year.
"Aged and healthy populations are more likely to be selectively depleted of pathogenic alleles, and therefore particularly suitable as a reference population for the major diseases of clinical and public health importance," the authors wrote. "However, reference studies of confirmed healthy elderly individuals have remained underrepresented in human genetics."
Even so, other teams have started putting together genetic resources for healthy aging cohorts. In particular, researchers from the Scripps Translational Science Institute and elsewhere have used genome sequencing to profile individuals who reached at least 80 without a chronic disease diagnosis or need for serious medication.
An analysis of sequences from 600 Wellderly participants published in Cell in 2016 highlighted rare and common variants that appeared to protect against cognitive decline or Alzheimer's disease risk, for example, while a more recent study in Nature Biotechnology compared induced pluripotent stem cells generated from five Wellderly study participants with those originating in 10 young or middle-aged individuals.
Given the large number of healthy, elderly participants already enrolled and sequenced for the new MGRB collection, the authors called it "a resource of international significance, which will be made broadly accessible to the clinical and genetic research community."
The team is making the database available to other researchers through a tiered, "hierarchical management system" that is meant to make the dataset amenable to research and clinical analyses without compromising the individuals' privacy and confidentiality.
"The overarching aim of the MGRB is to create a catalogue of genome-wide genetic variation in healthy, older individuals, and make data readily available to the clinical genetics and research community," the authors wrote, noting that secondary analyses may also reveal population-, phenotype-, and/or age-related variants, allele frequency patterns, and more.
"The MGRB will be the first catalogue of whole-genome variation across thousands of healthy elderly individuals," the authors concluded. "This will provide an important dataset, resource, and much-needed negative control population for clinical genetic and research use."