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Charlesworth D, Harkess A. Why should we study plant sex chromosomes? THE PLANT CELL 2024; 36:1242-1256. [PMID: 38163640 PMCID: PMC11062472 DOI: 10.1093/plcell/koad278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/10/2023] [Indexed: 01/03/2024]
Abstract
Understanding plant sex chromosomes involves studying interactions between developmental and physiological genetics, genome evolution, and evolutionary ecology. We focus on areas of overlap between these. Ideas about how species with separate sexes (dioecious species, in plant terminology) can evolve are even more relevant to plants than to most animal taxa because dioecy has evolved many times from ancestral functionally hermaphroditic populations, often recently. One aim of studying plant sex chromosomes is to discover how separate males and females evolved from ancestors with no such genetic sex-determining polymorphism, and the diversity in the genetic control of maleness vs femaleness. Different systems share some interesting features, and their differences help to understand why completely sex-linked regions may evolve. In some dioecious plants, the sex-determining genome regions are physically small. In others, regions without crossing over have evolved sometimes extensive regions with properties very similar to those of the familiar animal sex chromosomes. The differences also affect the evolutionary changes possible when the environment (or pollination environment, for angiosperms) changes, as dioecy is an ecologically risky strategy for sessile organisms. Dioecious plants have repeatedly reverted to cosexuality, and hermaphroditic strains of fruit crops such as papaya and grapes are desired by plant breeders. Sex-linked regions are predicted to become enriched in genes with sex differences in expression, especially when higher expression benefits one sex function but harms the other. Such trade-offs may be important for understanding other plant developmental and physiological processes and have direct applications in plant breeding.
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Affiliation(s)
- Deborah Charlesworth
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Alex Harkess
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
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2
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McDaniel SF. Divergent outcomes of genetic conflict on the UV sex chromosomes of Marchantia polymorpha and Ceratodon purpureus. Curr Opin Genet Dev 2023; 83:102129. [PMID: 37864936 DOI: 10.1016/j.gde.2023.102129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 09/22/2023] [Accepted: 09/24/2023] [Indexed: 10/23/2023]
Abstract
In species with separate sexes, the genome must produce two distinct developmental programs. Sexually dimorphic development may be controlled by either sex-limited loci or biased expression of loci transmitted through both sexes. Variation in the gene content of sex-limited chromosomes demonstrates that eukaryotic species differ markedly in the roles of these two mechanisms in governing sexual dimorphism. The bryophyte model systems Marchantia polymorpha and Ceratodon purpureus provide a particularly striking contrast. Although both species possess a haploid UV sex chromosome system, in which females carry a U chromosome and males carry a V, M. polymorpha relies on biased autosomal expression, while in C. purpureus, sex-linked genes drive dimorphism. Framing these genetic architectures as divergent outcomes of genetic conflict highlights comparative genomic analyses to better understand the evolution of sexual dimorphism.
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Affiliation(s)
- Stuart F McDaniel
- Biology Department, University of Florida, Gainesville, FL 32611-8525, USA.
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Garcia S, Janousek B, Pascual-Díaz JP, Renner SS. Sex-chrom v. 2.0: a database of green plant species with sex chromosomes. Chromosoma 2023; 132:55-58. [PMID: 36725728 DOI: 10.1007/s00412-023-00786-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 02/03/2023]
Affiliation(s)
- Sònia Garcia
- Institut Botànic de Barcelona (IBB-CSIC), Passeig del Migdia S/N, 08038, Barcelona, Catalonia, Spain.
| | - Bohuslav Janousek
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65, Brno, Czech Republic
| | - Joan Pere Pascual-Díaz
- Institut Botànic de Barcelona (IBB-CSIC), Passeig del Migdia S/N, 08038, Barcelona, Catalonia, Spain
| | - Susanne S Renner
- Department of Biology, Washington University, Saint Louis, MO, 63130, USA
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Carey SB, Lovell JT, Jenkins J, Leebens-Mack J, Schmutz J, Wilson MA, Harkess A. Representing sex chromosomes in genome assemblies. CELL GENOMICS 2022; 2. [PMID: 35720975 PMCID: PMC9205529 DOI: 10.1016/j.xgen.2022.100132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Sex chromosomes have evolved hundreds of independent times across eukaryotes. As genome sequencing, assembly, and scaffolding techniques rapidly improve, it is now feasible to build fully phased sex chromosome assemblies. Despite technological advances enabling phased assembly of whole chromosomes, there are currently no standards for representing sex chromosomes when publicly releasing a genome. Furthermore, most computational analysis tools are unable to efficiently investigate their unique biology relative to autosomes. We discuss a diversity of sex chromosome systems and consider the challenges of representing sex chromosome pairs in genome assemblies. By addressing these issues now as technologies for full phasing of chromosomal assemblies are maturing, we can collectively ensure that future genome analysis toolkits can be broadly applied to all eukaryotes with diverse types of sex chromosome systems. Here we provide best practice guidelines for presenting a genome assembly that contains sex chromosomes. These guidelines can also be applied to other non-recombining genomic regions, such as S-loci in plants and mating-type loci in fungi and algae.
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Affiliation(s)
- Sarah B Carey
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA.,HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - John T Lovell
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Jerry Jenkins
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Jim Leebens-Mack
- Department of Plant Biology, University of Georgia, Athens, GA 30602, USA
| | - Jeremy Schmutz
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA.,US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Melissa A Wilson
- School of Life Sciences, Center for Evolution and Medicine, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA
| | - Alex Harkess
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA.,HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
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Carey SB, Aközbek L, Harkess A. The contributions of Nettie Stevens to the field of sex chromosome biology. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210215. [PMID: 35306894 PMCID: PMC8941642 DOI: 10.1098/rstb.2021.0215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The early 1900s delivered many foundational discoveries in genetics, including re-discovery of Mendel's research and the chromosomal theory of inheritance. Following these insights, many focused their research on whether the development of separate sexes had a chromosomal basis or if instead it was caused by environmental factors. It is Dr Nettie M. Stevens' Studies in spermatogenesis (1905) that provided the unequivocal evidence that the inheritance of the Y chromosome initiated male development in mealworms. This result established that sex is indeed a Mendelian trait with a genetic basis and that the sex chromosomes play a critical role. In Part II of Studies in spermatogenesis (1906), an XY pair was identified in dozens of additional species, further validating the function of sex chromosomes. Since this formative work, a wealth of studies in animals and plants have examined the genetic basis of sex. The goal of this review is to shine a light again on Stevens’ Studies in spermatogenesis and the lasting impact of this work. We additionally focus on key findings in plant systems over the last century and open questions that are best answered, as in Stevens' work, by synthesizing across many systems. This article is part of the theme issue ‘Sex determination and sex chromosome evolution in land plants’.
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Affiliation(s)
- Sarah B Carey
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA.,HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Laramie Aközbek
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA.,HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Alex Harkess
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA.,HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
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Carey S, Yu Q, Harkess A. The Diversity of Plant Sex Chromosomes Highlighted through Advances in Genome Sequencing. Genes (Basel) 2021; 12:381. [PMID: 33800038 PMCID: PMC8000587 DOI: 10.3390/genes12030381] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 01/21/2023] Open
Abstract
For centuries, scientists have been intrigued by the origin of dioecy in plants, characterizing sex-specific development, uncovering cytological differences between the sexes, and developing theoretical models. Through the invention and continued improvements in genomic technologies, we have truly begun to unlock the genetic basis of dioecy in many species. Here we broadly review the advances in research on dioecy and sex chromosomes. We start by first discussing the early works that built the foundation for current studies and the advances in genome sequencing that have facilitated more-recent findings. We next discuss the analyses of sex chromosomes and sex-determination genes uncovered by genome sequencing. We synthesize these results to find some patterns are emerging, such as the role of duplications, the involvement of hormones in sex-determination, and support for the two-locus model for the origin of dioecy. Though across systems, there are also many novel insights into how sex chromosomes evolve, including different sex-determining genes and routes to suppressed recombination. We propose the future of research in plant sex chromosomes should involve interdisciplinary approaches, combining cutting-edge technologies with the classics to unravel the patterns that can be found across the hundreds of independent origins.
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Affiliation(s)
- Sarah Carey
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA;
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Qingyi Yu
- Texas A&M AgriLife Research, Texas A&M University System, Dallas, TX 75252, USA
| | - Alex Harkess
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA;
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
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