Evidence for Dosage Compensation in Coccinia grandis, a Plant with a Highly Heteromorphic XY System

Fruchard, Cecile; Badouin, Helene; Latrasse, David; Devani, Ravi S.; Muyle, Aline; Rhone, Benedicte; Renner, Susanne S.; Banerjee, Anjan K.; Bendahmane, Abdelhafid and Marais, Gabriel A. B. (2020): Evidence for Dosage Compensation in Coccinia grandis, a Plant with a Highly Heteromorphic XY System. In: Genes, Vol. 11, No. 7, 787

Abstract

About 15,000 angiosperms are dioecious, but the mechanisms of sex determination in plants remain poorly understood. In particular, how Y chromosomes evolve and degenerate, and whether dosage compensation evolves as a response, are matters of debate. Here, we focus on Coccinia grandis, a dioecious cucurbit with the highest level of X/Y heteromorphy recorded so far. We identified sex-linked genes using RNA sequences from a cross and a model-based method termed SEX-DETector. Parents and F1 individuals were genotyped, and the transmission patterns of SNPs were then analyzed. In the >1300 sex-linked genes studied, maximum X-Y divergence was 0.13-0.17, and substantial Y degeneration is implied by an average Y/X expression ratio of 0.63 and an inferred gene loss on the Y of similar to 40%. We also found reduced Y gene expression being compensated by elevated expression of corresponding genes on the X and an excess of sex-biased genes on the sex chromosomes. Molecular evolution of sex-linked genes in C. grandis is thus comparable to that in Silene latifolia, another dioecious plant with a strongly heteromorphic XY system, and cucurbits are the fourth plant family in which dosage compensation is described, suggesting it might be common in plants.

• Item Type: Journal article
• Faculties: Biology > Department Biology I
• Subjects: 500 Science > 570 Life sciences; biology
• Language: English