Riera-Begue, A. | bioRxiv Science

bioRxiv2025

An ancient X chromosomal region harbours three genes potentially controlling sex determination in Cannabis sativa

O_LISex determination mechanisms in dioecious plants remain poorly understood yet offer an excellent model system to study genetic changes underlying morphological evolution. C_LIO_LIWe investigated the genetic basis of sex determination in Cannabis sativa, combining QTL mapping in a segregating population, comparative transcriptomics between monoecious and dioecious cultivars, and a genomic analysis of X-Y chromosome divergence. C_LIO_LIQTL mapping identified Monoecy1, a locus on the X chromosome putatively controlling the monoecy-dioecy trait. This locus resides in the most ancient and diverged region of the sex chromosomes and contains three genes within 60,000 bp (CsREM16, lncREM16, and CsKAN4) with distinct sex-specific and monoecy-specific expression patterns. C_LIO_LIMonoecy1 harbours genes for male-female as well as monoecious-dioecious sex determination. We propose that the combinatorial interaction of CSREM16, lncREM16 and CsKAN4 provides a unifying genetic framework for understanding male-female and monoecious-dioecious sex determination in Cannabis sativa. C_LI

plant biology↗

bioRxiv2025

A simple and reliable PCR-based method to differentiate between XX and XY sex genotypes in Cannabis sativa

Cannabis sativa is mainly a dioecious plant, which means that female and male flowers develop on separate individuals, which is controlled by an XY sex determination system: females have two X chromosomes and male plants carry an X and a Y chromosome. C. sativa is a crop that has a wide variety of applications, some of which depend on the sex of the plant. Females are, for example, used for the cannabinoid production, as cannabinoids are produced in the female inflorescence. However, while adult C. sativa individuals present high sexual dimorphism, it is not possible to phenotypically distinguish male and female plants before flowering. Here we present the identification of a highly conserved sex marker, CsPDS5, and the development of a robust, reliable and affordable PCR-based method to determine the sex genotype. In contrast to other sex genotyping methods, our approach relies on a gene polymorphic between the X and Y chromosomes and therefore requires only a single PCR with one pair of primers. The method was tested in 14 cultivars and 6 crossings, with different tissues and developmental stages, on a total of 600 samples, with 100% accuracy. Our assay allows early sex identification and hemp selection, which is useful for both research and industrial purposes. Finally, the pipeline presented here to identify genes polymorphic between the X and Y chromosomes can serve to discover new sex markers, not only in C. sativa, but other dioecious plants and other organisms with 2 sexes.

plant biology↗