Browsing by Author "Sanderson, Brian J."
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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 A targeted sequence capture array for phylogenetics and population genomics in the Salicaceae(2020) Sanderson, Brian J.; DiFazio, Stephen P.; Cronk, Quentin C.B.; Ma, Tao; Olson, Matthew S.Premise The family Salicaceae has proved taxonomically challenging, especially in the genus Salix, which is speciose and features frequent hybridization and polyploidy. Past efforts to reconstruct the phylogeny with molecular barcodes have failed to resolve the species relationships of many sections of the genus. Methods We used the wealth of sequence data in the family to design sequence capture probes to target regions of 300–1200 bp of exonic regions of 972 genes. Results We recovered sequence data for nearly all of the targeted genes in three species of Populus and three species of Salix. We present a species tree, discuss concordance among gene trees, and present population genomic summary statistics for these loci. Conclusions Our sequence capture array has extremely high capture efficiency within the genera Populus and Salix, resulting in abundant phylogenetic information. Additionally, these loci show promise for population genomic studies.