biostudies-literatureWang DNSF Dimensions of Biodiversity ProgramFundamental Research Funds for the Central Universitiesthe National Key Research and Development Program of ChinaNational Natural Science Foundation of China200https://www.ebi.ac.uk/biostudies/studies/S-EPMC9502649biostudies-literatureUnknown23(1)<h4>Background</h4>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.<h4>Results</h4>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 evenGenome biologyRepeated turnovers keep sex chromosomes young in willows.PMC9502649418710443156112300115424792016YFD06001011542599154248615425092020SCUNL2072020SCUNL1032021YFD2200202SCU2021D0062021YFD22011003192206131500502Liu JOlson MYin TWang DFeng YZhou RSmart LBMa XZhang LMa TLi MYang WDiFazio SPLi YSanderson BJKeefover-Ring KZhang YWang YfalseRepeated turnovers keep sex chromosomes young in willows.<h4>Background</h4>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.<h4>Results</h4>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 even2022-01-01T00:00:00Z2022 Sep2026-05-28T03:30:45.847Z2025-02-19T00:44:14.91ZS-EPMC95026493615158110.1186/s13059-022-02769-w