ZW sex chromosome structure in Amborella trichopoda

作者：Sarah B. Carey, Laramie Aközbek, John T. Lovell, Jerry Jenkins, Adam Healey, Shengqiang Shu, Paul Grabowsk, Alan Yocca, Ada Stewart, Teresa Jones, Kerrie Barry, Shanmugam Rajasekar, Jayson Talag, Charles P. Scutt, Porter P. Lowry, Jérôme Munzinger, Eric B. Knox, Pamela S. Soltis, Pamela S. Soltis, Jane Grimwood, Jeremy Schmutz, James Leebens-Mack, Alex Harkess · 发表于：bioRxiv (Cold Spring Harbor Laboratory) · 年份：2024 · DOI：10.1101/2024.05.10.593579 · 被引用次数：2 · 研究领域：Plant Reproductive Biology、Plant Molecular Biology Research、Chromosomal and Genetic Variations

Sex chromosomes have evolved hundreds of times, and their recent origins in flowering plants can shed light on the early consequences of suppressed recombination. Amborella trichopoda, the sole species on a lineage that is sister to all other extant flowering plants, is dioecious with a young ZW sex determination system. Here we present a haplotype-resolved genome assembly, including highly-contiguous assemblies of the Z and W chromosomes. We identify a ~3-Megabase sex-determination region (SDR) captured in two strata that includes a ~300-Kilobase inversion that is enriched with repetitive sequence and contains a homolog of the Arabidopsis METHYLTHIOADENOSINE NUCLEOSIDASE (MTN1-2) genes, which are known to be involved in fertility. However, the remainder of the SDR does not show patterns typically found in non-recombining SDRs, like repeat accumulation and gene loss. These findings are consistent with the hypothesis that dioecy is recently derived in Amborella and the sex chromosome pair has not significantly degenerated.