Summary: A new study successfully isolated the distinct hidden pathways through which parental DNA shapes a child’s life. The research introduces a novel analytical framework that disentangles a child’s own direct genetic inheritance from the ambient environmental influence of their parents’ uninherited genes, a phenomenon known as “genetic nurture.”
By analyzing data from over 30,000 multi-generational families, investigators mapped the interplay between these indirect genetic factors and parent-of-origin effects (genetic imprinting), revealing that the domestic environment structured by parental DNA can match the potency of direct physical inheritance for traits like height, weight, and academic capacity.
Key Facts
- The Illusion of Direct Inheritance: Standard genetic mapping frequently makes the mistake of attributing an individual’s physical or behavioral traits entirely to their own sequenced DNA. In reality, a parent’s genetic profile systematically designs the home environment, behavioral parameters, and parental dynamics that guide a child’s biological development.
- The Dual-Biobank Scale: The international research team analyzed phenotypic and genetic datasets from more than 30,000 intact trios (mother, father, and child) harvested from the Norwegian Mother, Father, and Child Cohort and the Estonian Biobank.
- Quantifying Three Core Traits: The study mapped three highly scalable developmental metrics in children around age 10: height, Body Mass Index (BMI), and national standardized school test performance scores.
- The Shared Loci Discovery: The team discovered that identical chromosomal locations, or loci, underpin both direct genetic inheritance and indirect environmental nurture. This proves that the exact same parental genes dictate a child’s traits through two parallel tracks: the physical sequences passed down in the womb and the behavioral environments maintained in the household.
- Unmasking Parent-of-Origin Effects: The analytical model successfully separated genetic nurture from parent-of-origin mechanisms—where certain genes are chemically switched off in either the egg or the sperm, meaning a specific variant will only manifest a physical effect if inherited from the parent whose gene remains active.
- The Assortative Mating Variable: Unlike prior models, this framework mathematically accounts for non-random partnership patterns, correcting for the fact that couples frequently share highly similar traits (such as tall individuals choosing tall partners), which would otherwise skew the genetic modeling.
- Refining Personalized Medicine Targets: The study establishes a vital rule for biotech and pharmaceutical engineering: only genetic regions that demonstrate a direct genetic effect inside the child themselves serve as viable, high-probability drug targets for personalized medicine, whereas indirect environmental tracks must be managed through health and educational policy interventions.
Source: ISTA
Our parents’ genes, even the ones we didn’t inherit, leave a measurable lasting imprint on our lives. An international team led by researchers at the Institute of Science and Technology Austria (ISTA) and the Norwegian Institute of Public Health developed a new approach to analyze genetic data from tens of thousands of families.
The study, published this Tuesday in Cell Genomics, found that for height, body weight, and school test performance, the environment shaped by our parents’ genes can be nearly as important as the genes we actually inherited from them.
When scientists study the genetics of human characteristics or disease, they typically look at a person’s own DNA. But parents don’t just pass on genes—their genetic makeup may also shape the household environment, parenting behavior, and countless other factors that influence how a child develops.
This phenomenon, known as “genetic nurture”, complicates genetic studies, because differences among people can mistakenly be attributed entirely to their own DNA, when they are in fact partially driven by parental traits.
In addition to this, the same gene may behave differently depending on which parent passed it down. This phenomenon is known as the parent-of-origin effect, where some genes are naturally ‘switched off’ in either eggs or sperm—so that certain variants only have an effect if inherited from the parent where the gene is ‘on’. This may explain why some genetic disorders appear differently depending on the transmitting parent, or why identical genetic sequences can result in different physical or metabolic characteristics.
Untangling a child’s ‘own’ genetic contribution from the invisible genetic hand of their parents has been one of the central unsolved problems in human genetics. Now, an international team led by researchers at the Institute of Science and Technology Austria (ISTA) and the Norwegian Institute of Public Health has developed for the first time a method to clearly separate the multiple ways DNA influences a child’s characteristics.
“Indirect genetic effects and parent-of-origin effects are distinct phenomena that may explain how genes influence traits beyond the standard model of a person’s direct DNA. However, disentangling them to reveal their individual contributions and interplay has not been done before,” says Matthew Robinson, professor at ISTA. Robinson led the study together with first author Ilse Krätschmer, a postdoctoral researcher in his group, and Alexandra Havdahl, Center Director of the PsychGen Center for Genetic Epidemiology and Mental Health at the Norwegian Institute of Public Health in Oslo.
The long-lasting influence of parental genes
The team analyzed genetic and phenotypic data from over 30,000 families—each consisting of a mother, father, and child—drawn from two large-scale biobank studies: the Norwegian Mother, Father, and Child Cohort and the Estonian Biobank.
For each family, they looked at three measurable traits in the children: height, body mass index (BMI, a measure of body weight relative to height), and scores on national school tests taken around age 10. They then asked: for each trait, how much of the differences among children are attributable to the child’s own DNA, to each of the parents’ DNA acting through the environment they each create, and how much depends on whether DNA regions were inherited from the mother or the father.
Uniquely, their approach also accounts for the fact that couples often share similar traits, such as the tendency of tall people to partner with tall people, which can distort the modelling.
The team found that, of the variation attributable to genetics, a child’s own DNA is the single largest source for all three traits—but it is not the whole story. Combined, indirect parental effects and parent-of-origin effects are similarly substantial, meaning that ignoring them produces a significantly incomplete picture of how genes influence traits.
They also found that similar DNA regions, known to scientists as “loci”, underlie both direct and indirect genetic effects. “This suggests that the same loci shape a child’s traits both through the genes they carry and through the environment their parents create,” says Krätschmer.
Complex molecular mechanisms
The findings have broad implications for understanding how genetic and environmental factors combine to shape human development and also disease risk between generations.
Furthermore, environmental factors play the largest role for BMI and education scores, and the team’s results suggest that policies aimed at improving outcomes in health or education need to consider the powerful role of the family environment.
“Our findings reinforce that the relationship between genes and traits is genuinely complex and this has important implications for how we interpret genetic research,” says Robinson.
The framework can in principle be extended to many other traits and could help researchers better understand the genetics of conditions ranging from mental health disorders to metabolic disease.
“Ultimately, our method allows us to pinpoint if a genetic effect is only associated with the DNA of one of the parents and not the child’s own DNA,” says Krätschmer.
In this context, the researchers suggest that only regions of direct genetic effect, which tend to have a stronger impact within the person themselves, are likely to be good drug targets in personalized medicine.
Furthermore, this study may help the team better understand the effects of genetic imprinting—the molecular mechanism underlying the parent-of-origin effect.
“Interestingly, our results suggest that genetic imprinting may be widespread in humans, which is surprising, since the underlying mechanisms remain poorly understood,” Robinson concludes.
Key Questions Answered:
A: Genetic nurture refers to the way a parent’s genes shape the household environment and their parenting behavior, rather than the physical DNA they pass to their child. The study found that for traits like height, weight, and school performance, the environment created by a parent’s unique genetic makeup can be nearly as vital to a child’s success as the actual genes the child inherits.
A: This is due to a molecular process called the parent-of-origin effect, or genetic imprinting. Certain genes are naturally turned off in either the mother’s eggs or the father’s sperm. Because of this molecular toggle switch, a genetic trait or disorder may only active and impact the child if it is inherited from the specific parent whose gene remains turned on.
A: It acts as a filter for drug development. The researchers proved that because a parent’s genes can mimic genetic traits through the environment, scientists have often targeted the wrong areas. The study shows that only the genes showing a direct physical effect within the patient themselves are true candidates for personalized medicine and drug targeting.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this genetics and neurodevelopment research news
Author: Andreas Rothe
Source: ISTA
Contact: Andreas Rothe – ISTA
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Separating direct, indirect and parent-of-origin genetic effects in the human population” by Ilse Krätschmer, Laura Hegemann, Robin J. Hofmeister, Elizabeth C. Corfield, Mahdi Mahmoudi, Olivier Delaneau, Ole A. Andreassen, Archie Campbell, Caroline Hayward, the Estonian Biobank Research Team, Riccardo E. Marioni, Eivind Ystrom, and Alexandra Havdahl. Cell Genomics
DOI:10.1016/j.xgen.2026.101277
Abstract
Separating direct, indirect and parent-of-origin genetic effects in the human population
We introduce JODIE, a genetic joint modeling approach that estimates how DNA loci influence human traits by partitioning genetic effects into four components: direct effects (from a child’s alleles), indirect maternal and paternal effects (from parents’ alleles), and parent-of-origin (PofO) effects (dependent on parental transmission of alleles), while uniquely accounting for assortative mating.
We analyze 30,000 child-mother-father trios from the Estonian Biobank and the Norwegian Mother, Father, and Child Cohort, focusing on height, body mass index, and childhood educational test scores. We find direct effects to be the largest contributor to trait variation, but combined, indirect parental and PofO effects are similarly substantial.
We support our results by within-family genome-wide association testing and identify 276 independently associated DNA regions with a complex interplay between direct, indirect, and PofO effects.
By joint modeling, we show that direct, indirect, and PofO effects collectively shape human phenotypic variation across loci genome-wide.
