Summary: A new study isolates the distinct, hidden pathways through which parental DNA shapes a child’s development. The research introduces a joint modeling framework that separates a child’s direct genetic inheritance from the environmental influence of parents’ non-transmitted genes — a phenomenon called “genetic nurture” — and distinguishes these from parent-of-origin (imprinting) effects.
By analyzing genomic and phenotypic data from more than 30,000 mother-father-child trios, researchers mapped how indirect parental effects and parent-of-origin mechanisms interact with direct genetic inheritance. They found that the home environment structured by parental genetics can rival the influence of a child’s own DNA for traits such as height, body mass index (BMI), and school test performance.
Key Facts
- The illusion of pure direct inheritance: Standard genetic analyses often attribute trait variation solely to an individual’s own DNA. This study shows parental genomes also shape the environment and parenting behaviors that systematically affect a child’s development.
- Large, multi-biobank data: The team examined over 30,000 intact family trios drawn from the Norwegian Mother, Father, and Child Cohort and the Estonian Biobank, combining genotype and phenotype records to enable within-family comparisons.
- Three core childhood traits: Analyses focused on height, BMI (weight relative to height), and national standardized school test scores measured around age 10, traits that are highly polygenic and developmentally relevant.
- Shared loci for direct and indirect effects: Many of the same chromosomal regions (loci) contribute both through direct inheritance and via parental influence on the environment, implying parallel pathways from the same genetic variants.
- Separating imprinting from nurture: The model distinguishes parent-of-origin effects — where a gene’s impact depends on whether it was inherited from the mother or father due to imprinting — from indirect parental environmental effects.
- Accounting for assortative mating: Unlike earlier approaches, the framework corrects for non-random mating (for example, tall individuals pairing with tall partners), which otherwise biases estimates of genetic and environmental contributions.
- Implications for precision medicine: The study emphasizes that only loci demonstrating a clear direct effect within the individual are reliable molecular targets for drug development; indirect effects are better addressed through social, educational, and public health interventions.
Source: ISTA
Parents’ genes, even those not transmitted to a child, leave measurable, long-lasting marks on development. 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 joint modeling method to parse genetic contribution across family members. Their work, published in Cell Genomics, demonstrates that for height, body weight, and school performance the environment shaped by parental genomes can be nearly as influential as the child’s own genome.
Conventional genetic studies typically analyze an individual’s genotype and attribute trait variation to that DNA alone. But parents’ genotypes also shape the rearing environment — the resources, behaviors, and routines that affect biological and cognitive development. This indirect route, genetic nurture, makes it harder to isolate the child’s direct genetic effects. Further complicating the picture, some genes are subject to parent-of-origin effects: chemical modifications can silence a gene on one parental chromosome so that a variant only manifests if inherited from the parent whose copy remains active.
The researchers used a method called JODIE to jointly estimate four components of genetic influence: direct effects from the child’s alleles, indirect maternal and paternal effects from parental alleles acting via the environment, and parent-of-origin effects that depend on which parent transmitted a given allele. The model also explicitly adjusts for assortative mating to avoid inflation of genetic estimates caused by partner similarity.
Across the three traits, direct genetic effects remained the single largest contributor to variation. However, the combined influence of indirect parental effects and parent-of-origin effects was substantial and cannot be ignored. The team validated findings with within-family genome-wide association tests and identified 276 independent genomic regions where direct, indirect, and parent-of-origin mechanisms interact in complex ways.
Complex molecular mechanisms and policy relevance
The study’s results have broad implications for how we interpret genetic associations and for translational research. For traits like BMI and educational achievement, environmental contributions — many of which are shaped by parental genetics — play a dominant role. That suggests policy interventions focused on family environments, education, and public health could effectively modify outcomes that might otherwise be mischaracterized as purely genetic.
For biomedical research, the findings issue a clear guideline: genetic loci with demonstrated direct effects in the individual are the strongest candidates for therapeutic targeting, whereas loci acting primarily through parental environment are better addressed by social and behavioral interventions.
Key Questions Answered:
A: Genetic nurture describes how a parent’s genes affect the household environment and parenting practices, rather than the child’s transmitted DNA. The study shows these indirect effects can be nearly as important as inherited genes for traits such as height, weight, and school performance.
A: Through parent-of-origin effects (genetic imprinting), some genes are selectively silenced on either the maternal or paternal chromosome. Consequently, a variant’s impact can depend on which parent transmitted it, producing different outcomes even with the same DNA sequence.
A: The research helps distinguish loci that act directly within the patient from loci whose apparent effects arise through parental influence. Drugs and precision therapies should prioritize regions with direct intra-individual effects, while indirect effects are more appropriately targeted by environmental or policy measures.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full by editorial staff.
- Additional explanatory context was added by the editorial team.
About this genetics and neurodevelopment research news
Author: Andreas Rothe
Source: ISTA
Contact: Andreas Rothe – ISTA
Image: Image credited to Neuroscience News
Original Research: Open access. “Separating direct, indirect and parent-of-origin genetic effects in the human population” by Ilse Krätschmer et al., published in 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 loci-level effects into four components: direct effects from a child’s alleles, indirect maternal and paternal effects from parental alleles acting via the environment, and parent-of-origin effects dependent on allele transmission. The method uniquely accounts for assortative mating. Using 30,000 trios from the Estonian Biobank and the Norwegian Mother, Father, and Child Cohort and focusing on height, BMI, and childhood educational test scores, the study finds direct effects are the largest single contributor to trait variation but that indirect parental and parent-of-origin effects together contribute substantially. Within-family genome-wide association testing supports the findings and identifies 276 independently associated regions, showing a complex interplay of direct, indirect, and parent-of-origin effects across the genome.