Summary: A new international study separates the different, hidden pathways through which parental DNA shapes a child’s traits. The research presents a novel analytical framework that disentangles a child’s direct genetic inheritance from the environmental influence produced by the parents’ genes that the child did not inherit—a process called “genetic nurture.”
Analyzing genetic and phenotypic data from more than 30,000 mother–father–child trios drawn from large biobank studies, researchers mapped how indirect parental genetic effects and parent-of-origin influences (genetic imprinting) combine with the child’s own DNA to shape traits such as height, body mass index (BMI), and school test performance.
Key Facts
- The limits of attributing traits to an individual’s DNA: Standard genetic studies often credit a person’s characteristics entirely to their own sequenced DNA. This work shows that parental genomes also shape the child’s environment—home conditions, parenting styles, and social influences—which in turn affect development.
- Large-scale, family-based data: The analysis used genetic and trait data from over 30,000 intact trios assembled from the Norwegian Mother, Father, and Child Cohort and the Estonian Biobank, enabling robust within-family comparisons.
- Three measurable child traits: Researchers focused on height, BMI (weight relative to height), and national standardized school test scores assessed around age 10, tracing how much variation is explained by direct versus indirect genetic channels.
- Shared genetic loci for direct and indirect effects: The study identified the same chromosomal regions (loci) as drivers of both direct inheritance and indirect parental influence, indicating that identical genes can shape traits both through the allele a child carries and through the environment their parents create.
- Separating parent-of-origin mechanisms: The model distinguishes genetic nurture from parent-of-origin effects (genetic imprinting), where certain alleles are expressed only when transmitted from one parent because the corresponding copy from the other parent is epigenetically silenced.
- Accounting for assortative mating: The framework corrects for non-random mating patterns—when partners choose similar characteristics (for example, tall individuals pairing with tall partners)—which can otherwise bias genetic estimates.
- Implications for precision medicine and policy: The results show that only loci with a direct effect inside the individual are appropriate targets for personalized drug development, while loci influencing outcomes indirectly through parental behavior or household environment are better addressed via public health, education, and social policy interventions.
Source: ISTA
Overview
Researchers from the Institute of Science and Technology Austria (ISTA) and the Norwegian Institute of Public Health developed a method to parse multiple genetic pathways that shape human traits. Published in Cell Genomics, the study demonstrates that for traits like height, body weight, and school performance, the environment produced by parents’ genes can be almost as influential as the genes transmitted to the child.
When geneticists study the biology of traits and disease risk they typically examine the individual’s own genotype. But a parent’s genetic profile can influence the child indirectly by structuring the household environment, behaviours, and opportunities a child experiences. This indirect influence—genetic nurture—can make it appear that the child’s own DNA fully accounts for observed differences when parental effects also play a major role.
Parent-of-origin effects add a second layer of complexity. Because some genes are epigenetically silenced in either the egg or the sperm, identical DNA sequences can produce different outcomes depending on whether they came from the mother or the father. That mechanism helps explain why particular disorders, growth patterns, or metabolic traits may differ depending on the transmitting parent.
The long-lasting influence of parental genes
The study analyzed more than 30,000 child–mother–father trios from two major biobank resources to quantify how much variation in height, BMI, and educational test scores is attributable to four components: the child’s direct alleles, maternal indirect effects, paternal indirect effects, and parent-of-origin (PofO) transmission. The analysis explicitly models assortative mating so that parental similarity does not inflate estimates of genetic influence.
Results show that a child’s own DNA is the largest single contributor to trait variation across the three measures. However, when combined, indirect parental effects and parent-of-origin effects account for a similarly substantial portion of the genetic variance. Ignoring these indirect channels therefore yields an incomplete and potentially misleading picture of genetic architecture.
Notably, many of the same loci contribute to both direct and indirect effects, indicating that the same genomic regions shape a child’s phenotype both through biological inheritance and through environmental pathways established by parents.
Complex molecular mechanisms and implications
These findings highlight how genetic and environmental influences interact across generations to shape development and disease susceptibility. For BMI and educational outcomes, environmental pathways play a particularly large role, underscoring the importance of family and social context when designing interventions.
For biomedical research, the study provides a practical guide: prioritize loci with clear direct effects in the individual when selecting drug targets for personalized medicine. Indirectly acting loci, which shape outcomes by altering parental behavior or household conditions, are more appropriately targeted through policy, education, or behavioral interventions.
The researchers also provide evidence that genetic imprinting may be more widespread than previously recognized, an observation that calls for deeper study into the epigenetic mechanisms that govern parent-of-origin expression.
Key Questions Answered:
A: Genetic nurture describes how a parent’s genetic makeup shapes the family environment and parenting behaviors rather than the DNA the child inherits. For traits such as height, weight, and academic performance, the parental environment influenced by parental genes can be nearly as influential as the child’s inherited genes.
A: This is due to parent-of-origin effects or genetic imprinting. Some gene copies are epigenetically turned off in one parent’s germline (egg or sperm), so an allele’s effect may depend on which parent passed it on.
A: The study clarifies that only loci showing a direct effect inside the individual are strong candidates for drug targeting. Genetic regions that influence outcomes indirectly through parental behavior should be addressed by social, educational, or public-health policies rather than drug development.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was provided by editorial 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
The authors introduce JODIE, a joint genetic modeling approach that partitions genetic influence at DNA loci into four components: direct effects from the child’s alleles, indirect maternal and paternal effects from parents’ alleles (genetic nurture), and parent-of-origin effects dependent on whether an allele was transmitted from the mother or father. The method uniquely accounts for assortative mating.
Applying JODIE to 30,000 child–mother–father trios from the Estonian Biobank and the Norwegian Mother, Father, and Child Cohort and focusing on height, BMI, and childhood educational test scores, the team finds that direct effects are the largest single contributor to trait variation. Yet combined indirect parental and parent-of-origin effects are similarly substantial. Within-family genome-wide association testing supports these results and identifies 276 independently associated genomic regions with complex interplay among direct, indirect, and parent-of-origin effects. Joint modeling demonstrates that all three classes of effects collectively shape phenotypic variation across the genome.