by Sanjukta Mondal, Phys.org
edited by Lisa Lock, reviewed by Robert Egan
Certain genetic mutations can have different outcomes depending on whether one inherits from their mother or their father. This phenomenon is known as parent-of-origin effects (POEs), where certain genes are switched on or off depending on their parental source. While scientists have been aware of this behavior for some time, little is known about the genetic traits of POEs, primarily due to the unavailability of parental genetic data.
A recent study published in Nature
More than a third of these POEs displayed what researchers called bipolar effects, where maternal and paternal versions of the same allele showed opposite outcomes. In other words, if the offspring inherited the allele from one parent it increased the possibility of trait, while inheriting it from the other could lower it. Such genetic push and pull was especially observed in traits tied to growth and metabolic issues, including Type 2 diabetes risk and triglyceride levels.
Humans and other mammals inherit two copies of every gene, one from each parent, and in most cases both the genes are either turned on or off. In some scenarios, however, selective expression of only one parental gene is observed—this is known as genomic imprinting.
A key mechanism for driving POEs, genomic imprinting is thought to arise from an evolutionary genetic rivalry between the parental genes over resource allocation to offspring, sometimes pushing those traits in completely opposite directions. Despite the wide acceptance of this parental conflict hypothesis, it hasn’t been systematically tested across many traits.
Conventional methods for studying POEs require genetic information from both parents to identify which allele was inherited from which parent. The new technique presented in this study inferred this information using genomic data from any available relatives.
- The researchers used interchromosomal phasing, a method that uses data collected from different chromosomes to figure out which genetic variants are inherited together. They also analyzed mitochondrial data and sex-dependent traits that are passed down through generations.
Using this system, the researchers identified more than 30 POEs, including many previously unreported ones. To validate the method, the researchers replicated the findings in additional cohorts: 85,050 participants from the Estonian Biobank and 42,346 children from the Norwegian Mother, Father and Child Cohort Study (MoBa), bringing the combined sample size to as many as 236,781 individuals, one of the largest POE-informed cohort thus far.
The researchers noted that the results highlighted the contribution of POEs in determining complex traits and also supported the parental conflict hypothesis. They suggest incorporating POEs more widely into genetic research to uncover the molecular mechanisms behind these effects and their implications on one’s health.
Written for you by our author Sanjukta Mondal, edited by Lisa Lock, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You’ll get an ad-free account as a thank-you.
More information: Robin J. Hofmeister et al, Parent-of-origin effects on complex traits in up to 236,781 individuals, Nature (2025). DO
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