Cereal root systems are critical for nutrient and water uptake as well as for anchorage and thus for plant productivity. This review synthesizes the current understanding of the morphological and cell...

Spatially resolved gene expression during barley development was done by integrating an scRNA-seq dataset from cells with unknown position with spatial transcriptomics. This dataset is publicly availa...

When a maize plant is attacked by the fungus Ustilago maydis, tumor-like tissue growths occur at the site of infection. How the pathogen causes this response in its host has long been unknown. But a…

Pflanzen, die mit neuen gentechnischen Techniken (NGTs) verändert werden, sollen in der EU zukünftig ähnlich reguliert werden, wie Züchtungen mit konventionellen Methoden. Darauf haben sich Vertreter:...

Studierenden- und Mitarbeiterportal der Technische Universität München

Podcast-Folge · Alles gesagt? · 29.08.2025 · 4 Std. 13 Min.

Background Classical genetic concepts to explain heterosis attribute the superiority of F1-hybrids over their homozygous parents to the complementation of unfavorable by beneficial alleles (dominance) or to heterozygote advantage (overdominance). Here we analyze 112 intermated B73xMo17 recombinant inbred lines of maize and their backcrosses to their original parents B73 and Mo17 to obtain hybrids with an average heterozygosity of ~ 50%. This genetic architecture allows studying the influence of homozygous and heterozygous genomic regions on gene expression in hybrids. Results We demonstrate that single parent expression (SPE) complementation explains between − 8% and 29% of the mid-parent heterotic variance in these hybrids. In this expression pattern, consistent with dominance, genes are active in only one parent and in the hybrid, thus increasing the number of expressed genes in hybrids. Furthermore, we establish that eQTL regulating SPE genes are predominantly located in heterozygous regions of the genome. Finally, we identify an SPE gene that regulates lateral root density in hybrids. Remarkably, the activity of this gene depends on the presence of a Mo17 allele in an eQTL that regulates this gene. Conclusions Here we show that dominance of SPE genes influences the number of active genes in hybrids, while heterozygosity is instrumental for the regulation of these genes. This finding supports the notion that the genetic constitution of distant regulatory elements is instrumental for the activity of heterosis-associated genes. In summary, our results connect genetic variation at regulatory loci and the degree of heterozygosity with phenotypic variation of heterosis via SPE complementation.