The asparagus genome sheds light on the origin and evolution of a young Y chromosome.

Authors: Harkess, Alex and Zhou, Jinsong and Xu, Chunyan and Bowers, John E and Van der Hulst, Ron and Ayyampalayam, Saravanaraj and Mercati, Francesco and Riccardi, Paolo and McKain, Michael R and Kakrana, Atul and Tang, Haibao and Ray, Jeremy and Groenendijk, John and Arikit, Siwaret and Mathioni, Sandra M and Nakano, Mayumi and Shan, Hongyan and Telgmann-Rauber, Alexa and Kanno, Akira and Yue, Zhen and Chen, Haixin and Li, Wenqi and Chen, Yanling and Xu, Xiangyang and Zhang, Yueping and Luo, Shaochun and Chen, Helong and Gao, Jianming and Mao, Zichao and Pires, J Chris and Luo, Meizhong and Kudrna, Dave and Wing, Rod A and Meyers, Blake C and Yi, Kexian and Kong, Hongzhi and Lavrijsen, Pierre and Sunseri, Francesco and Falavigna, Agostino and Ye, Yin and Leebens-Mack, James H and Chen, Guangyu

Sex chromosomes evolved from autosomes many times across the eukaryote phylogeny. Several models have been proposed to explain this transition, some involving male and female sterility mutations linked in a region of suppressed recombination between X and Y (or Z/W, U/V) chromosomes. Comparative and experimental analysis of a reference genome assembly for a double haploid YY male garden asparagus (Asparagus officinalis L.) individual implicates separate but linked genes as responsible for sex determination. Dioecy has evolved recently within Asparagus and sex chromosomes are cytogenetically identical with the Y, harboring a megabase segment that is missing from the X. We show that deletion of this entire region results in a male-to-female conversion, whereas loss of a single suppressor of female development drives male-to-hermaphrodite conversion. A single copy anther-specific gene with a male sterile Arabidopsis knockout phenotype is also in the Y-specific region, supporting a two-gene model for sex chromosome evolution.

Journal: Nature communications
DOI: 10.1038/s41467-017-01064-8
Year: 2017

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