A genetic technique can identify which parts of your genome came from your biological mother and which from your biological father. The method could be useful in cases where an individual is carrying a disease-associated gene variant by helping to establish which other family members should consider undergoing screening for the gene.
Steven Jones at the University of British Columbia, Canada, and his colleagues developed the approach using DNA sequence data from the genomes of five people, which had been analysed in previous studies. The researchers also had access to genomes belonging to the biological parents of each of the five people.
Each genome tested contained 22 pairs of non-sex chromosomes, called autosomes, with each pair containing one chromosome from the biological mother and one from the biological father.
The team applied an existing technique called Strand-seq to sort all autosomes into two sets, one from each parent, but this didn’t establish which parent was which.
To identify whether an autosome came from the biological mother or father, the researchers looked for evidence of a type of epigenetic marker called DNA methylation in around 200 regions of the DNA.
The researchers were able to predict which biological parent was the source of a particular chromosome
“About 200 sites in the genome are methylated only in the paternal or only in the maternal chromosome,” says Shai Carmi at the Hebrew University of Jerusalem, Israel, who wasn’t involved in the study. “These sites are well known, and the parent-specific methylation is robust.”
Using these sites as a guide, Jones and his colleagues were then able to predict which biological parent was the source of a particular autosome. They then confirmed their results by looking at the genomes of the biological parents.
“It’s a very, very cool study,” says Carmi although he thinks applications will be limited by the high cost of the equipment.
