Skip to main content
Dryad

Data and code from: Departures from Mendelian inheritance of EPSPS gene copies in a herbicide-resistant weed

Yakimowski, Sarah1; Han, Lisa2; Dungey, Kathryn3

Published May 01, 2026 on Dryad. https://doi.org/10.5061/dryad.sbcc2frjv

Data files

May 01, 2026 version files 157.90 KB

Click names to download individual files

Abstract

Here we report on inheritance and intra-individual variation in gene copy number associated with rapid evolution of herbicide resistance in the dioecious, agricultural weed Amaranthus palmeri. Copy number variation for glyphosate resistance gene EPSPS was quantified using digital droplet PCR within individuals, and for parents and offspring of controlled crosses with copy number ranging from 1 to ~160. The non-linear pattern of gene copy number inheritance from parent to offspring exhibits shifting directionality. Below the threshold of ~33 copies, the slope of the parent-offspring relation is high (1.60) because parents with fewer gene copies yield similar or increased mean offspring copy numbers, relative to parents. In contrast, above the threshold, the slope is low (0.21), and offspring of high copy number parents carry increasingly fewer EPSPS copies than parents. Intra-individual variance in copy number increases with mean individual copy number, likely contributing to variation in offspring copy number, but not sufficient to explain extreme transgressive copy number variants, nor the loss of high copy number. In short, copy number is less stable and transmitted to offspring at a lower rate in parents with more copies. This suggests a constraint on the evolution of herbicide resistance through increased EPSPS copy number.