Uncovering the Secrets of the Peanut Genome
Background: Gaps in the Peanut Genome
A study reporting chromosome-end-to-end genome assemblies for two diploid peanut progenitor lineages and four cultivated allotetraploid accessions was published in Nature Genetics. The researchers analyzed these telomere-to-telomere (T2T) genomes together with resequencing data from 521 accessions to identify genetic differences associated with oil content and seed size.
Cultivated peanut carries A and B subgenomes derived from different ancestors. Earlier peanut genome assemblies were available, but many retained sequence gaps or sequences that could not be assigned to chromosomal locations. These gaps constrained comparisons of structural variants, such as large DNA insertions and deletions, and centromere evolution.
Key Findings: Six Reference Genomes and Trait-Associated Candidates
The researchers combined high-accuracy long DNA reads, ultra-long reads, and chromosome-contact information to build reference genomes for six accessions. Assembly sizes ranged from approximately 1.18–2.63 Gb, and all assemblies reported in the table had zero sequence gaps. The study did not assemble all 521 accessions to T2T completeness.
Comparative analyses found different patterns of transposable elements, chromosome rearrangements, and centromere changes in the two subgenomes. Transposable elements are DNA elements that can move or be copied within a genome. The findings show that the two subgenomes have not changed symmetrically, even within cultivated peanut.
Genome-wide association analysis (GWAS) identified AhWRI1 as a candidate associated with oil content and AhGSA1 as a candidate associated with seed size and weight. Among 153 accessions with RNA-sequencing data, the Hap1 and Hap2 AhWRI1 genotype groups had mean oil contents of 48.41% and 54.10%, respectively. This was a comparison between groups of accessions; it does not mean that genetic manipulation increased oil content by that amount. Assays of promoter activity, which regulates gene expression, and protein–DNA binding experiments also supported differences in the regulation of AhWRI1 expression. For AhGSA1, associations were also observed among promoter variants, expression levels, and seed size and weight.
Significance and Outlook: Reference Data to Narrow Breeding Candidates
Rather than being the first decoding of the peanut genome, this study provides highly complete reference genomes from multiple accessions, enabling more precise comparisons of structural variation and trait differences. The researchers also analyzed gene expression and metabolites during seed development in two cultivated accessions and proposed candidates linked to lipid accumulation and seed-coat pigments.
These data may help future studies select breeding material for oil content or seed traits. However, associations among accessions and regulatory activity in experimental systems do not guarantee the performance of a new variety. The effects of candidate variants in peanut itself, and trait changes under different growing conditions, require validation. Direct effects on human health or diet were not evaluated in this study.
The material studied and the analytical findings are described in the Nature Genetics article.
Nature Genetics, Published online: 24 April 2026; doi:10.1038/s41588-026-02577-z Telomere-to-telomere genome assemblies for two diploid and four tetraploid peanut varieties provide insights into peanut genome organization, evolutionary dynamics, and phenotypic differentiation.
Breeders can use these reference genomes and variant data to identify genotypes associated with oil content or seed size and help narrow the accessions considered for crossing. For example, variants near AhWRI1 and AhGSA1 could serve as candidate selection markers, then be evaluated in actual crossing populations to determine whether they are inherited together with the target traits. The publicly available genomes and annotations also provide a basis for revisiting structural variants that were difficult to compare in earlier assemblies. The usefulness of selection markers, effects across environments, and accompanying changes in other traits remain to be validated. These findings alone do not demonstrate the development of an improved variety or health benefits.