Browsing by Author "Wang, Deyan"
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Item Evolution of a ZW sex chromosome system in willows(2023) Hu, Nan (TTU); Sanderson, Brian J.; Guo, Minghao (TTU); Feng, Guanqiao (TTU); Gambhir, Diksha (TTU); Hale, Haley; Wang, Deyan; Hyden, Brennan; Liu, Jianquan; Smart, Lawrence B.; DiFazio, Stephen P.; Ma, Tao; Olson, Matthew S. (TTU)Transitions in the heterogamety of sex chromosomes (e.g., XY to ZW or vice versa) fundamentally alter the genetic basis of sex determination, however the details of these changes have been studied in only a few cases. In an XY to ZW transition, the X is likely to give rise to the W because they both carry feminizing genes and the X is expected to harbour less genetic load than the Y. Here, using a new reference genome for Salix exigua, we trace the X, Y, Z, and W sex determination regions during the homologous transition from an XY system to a ZW system in willow (Salix). We show that both the W and the Z arose from the Y chromosome. We find that the new Z chromosome shares multiple homologous putative masculinizing factors with the ancestral Y, whereas the new W lost these masculinizing factors and gained feminizing factors. The origination of both the W and Z from the Y was permitted by an unexpectedly low genetic load on the Y and this indicates that the origins of sex chromosomes during homologous transitions may be more flexible than previously considered.Item A General Model to Explain Repeated Turnovers of Sex Determination in the Salicaceae(2021) Yang, Wenlu; Wang, Deyan; Li, Yiling; Zhang, Zhiyang; Tong, Shaofei; Li, Mengmeng; Zhang, Xu; Zhang, Lei; Ren, Liwen; Ma, Xinzhi; Zhou, Ran; Sanderson, Brian J.; Keefover-Ring, Ken; Yin, Tongming; Smart, Lawrence B.; Liu, Jianquan; DiFazio, Stephen P.; Olson, Matthew; Ma, TaoDioecy, the presence of separate sexes on distinct individuals, has evolved repeatedly in multiple plant lineages. However, the specific mechanisms by which sex systems evolve and their commonalities among plant species remain poorly understood. With both XY and ZW sex systems, the family Salicaceae provides a system to uncover the evolutionary forces driving sex chromosome turnovers. In this study, we performed a genome-wide association study to characterize sex determination in two Populus species, P. euphratica and P. alba. Our results reveal an XY system of sex determination on chromosome 14 of P. euphratica, and a ZW system on chromosome 19 of P. alba. We further assembled the corresponding sex-determination regions, and found that their sex chromosome turnovers may be driven by the repeated translocations of a Helitron-like transposon. During the translocation, this factor may have captured partial or intact sequences that are orthologous to a type-A cytokinin response regulator gene. Based on results from this and other recently published studies, we hypothesize that this gene may act as a master regulator of sex determination for the entire family. We propose a general model to explain how the XY and ZW sex systems in this family can be determined by the same RR gene. Our study provides new insights into the diversification of incipient sex chromosomes in flowering plants by showing how transposition and rearrangement of a single gene can control sex in both XY and ZW systems.Item Repeated turnovers keep sex chromosomes young in willows(2022) Wang, Deyan; Li, Yiling; Li, Mengmeng; Yang, Wenlu; Ma, Xinzhi; Zhang, Lei; Wang, Yubo; Feng, Yanlin; Zhang, Yuanyuan; Zhou, Ran; Sanderson, Brian J (TTU); Keefover‑Ring, Ken; Yin, Tongming; Smart, Lawrence B; DiFazio, Stephen P; Liu, Jianquan; Olson, Matthew (TTU); Ma, TaoBackground Salicaceae species have diverse sex determination systems and frequent sex chromosome turnovers. However, compared with poplars, the diversity of sex determination in willows is poorly understood, and little is known about the evolutionary forces driving their turnover. Here, we characterized the sex determination in two Salix species, S. chaenomeloides and S. arbutifolia, which have an XY system on chromosome 7 and 15, respectively. Results Based on the assemblies of their sex determination regions, we found that the sex determination mechanism of willows may have underlying similarities with poplars, both involving intact and/or partial homologs of a type A cytokinin response regulator (RR) gene. Comparative analyses suggested that at least two sex turnover events have occurred in Salix, one preserving the ancestral pattern of male heterogamety, and the other changing heterogametic sex from XY to ZW, which could be partly explained by the “deleterious mutation load” and “sexually antagonistic selection” theoretical models. We hypothesize that these repeated turnovers keep sex chromosomes of willow species in a perpetually young state, leading to limited degeneration. Conclusions Our findings further improve the evolutionary trajectory of sex chromosomes in Salicaceae species, explore the evolutionary forces driving the repeated turnovers of their sex chromosomes, and provide a valuable reference for the study of sex chromosomes in other species.