Switching it up: algal insights into sexual transitions

Coelho, Susana M.; Umen, James G.

doi:10.1007/s00497-021-00417-0

Cited by 14 publications

(13 citation statements)

References 69 publications

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“…Brown seaweed are eukaryotic organisms spanning a rich variety of morphologies, life cycles and sexual systems 8,14,15 . Using high-quality reference genomes (Denoeud et al, submitted), supplemented with genetic and HiC physical maps (see methods), we generated chromosome or near-chromosome level genome assemblies of nine representative brown algal species.…”

Section: Identification and Characterization Of Brown Algal Sex Chrom...mentioning

confidence: 99%

Origin and evolutionary trajectories of brown algal sex chromosomes

Barrera-Redondo,

Lipinska,

Liu

et al. 2024

Preprint

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Sex chromosomes fall into three classes: XX/XY, ZW/ZZ and U/V systems. The rise, evolution and demise of U/V systems have remained enigmatic to date. Here, we analyze genomes spanning the entire brown algal phylogeny to decipher their sex-determination evolutionary history. The birth of U/V sex chromosomes evolved more than 250 million years ago, when a pivotal male-determinant located in a discrete region in proto-U and proto-V chromosomes ceased recombining. Over time, nested inversions led to step-wise expansions, accompanying increasing morphological complexity and sexual differentiation of brown seaweeds. Unlike XX/XY and ZW/ZZ, U/V evolve mainly by gene gain, showing minimal degeneration. They are structurally dynamic, and act as genomic 'cradles' fostering the birth of new genes. Our analyses show that hermaphroditism arose from ancestral males that acquired U-specific genes by ectopic recombination, and that in the transition from a U/V to an XX/XY system, V-specific genes moved down the genetic hierarchy of sex determination. Both events lead to the demise of U and V and erosion of their specific genomic characteristics. Taken together, our findings offer a comprehensive model of U/V sex chromosome evolution.

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Section: Identification and Characterization Of Brown Algal Sex Chrom...mentioning

confidence: 99%

Origin and evolutionary trajectories of brown algal sex chromosomes

Barrera-Redondo,

Lipinska,

Liu

et al. 2024

Preprint

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“…As with C. reinhardtii, ectopic expression of MID in female (plus) gametes of the related alga, V. carteri, leads to a pseudo-male gametic phenotype (Geng et al, 2014), and MID orthologs can be functionally substituted between different species of algae (Geng et al, 2018). These findings demonstrate a conserved role of MID in algal mating type determination, and indicate that plus/female gamete differentiation is the default state in these systems (Goodenough and Heitman, 2014;Coelho and Umen, 2021).…”

Section: Mating Type Determinationmentioning

confidence: 75%

HAP2-Mediated Gamete Fusion: Lessons From the World of Unicellular Eukaryotes

Pinello

Clark

2022

Front. Cell Dev. Biol.

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Most, if not all the cellular requirements for fertilization and sexual reproduction arose early in evolution and are retained in extant lineages of single-celled organisms including a number of important model organism species. In recent years, work in two such species, the green alga, Chlamydomonas reinhardtii, and the free-living ciliate, Tetrahymena thermophila, have lent important new insights into the role of HAP2/GCS1 as a catalyst for gamete fusion in organisms ranging from protists to flowering plants and insects. Here we summarize the current state of knowledge around how mating types from these algal and ciliate systems recognize, adhere and fuse to one another, current gaps in our understanding of HAP2-mediated gamete fusion, and opportunities for applying what we know in practical terms, especially for the control of protozoan parasites.

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“…Large eggs and small spermatozoids were then produced from the female and male gametangia, respectively, implying the sexual dimorphism in S. japonica (commonly referred to as kelp). This kelp is hence an oogamous species with dioicous gametophytes as proposed by Luthringer et al (2014); Coelho et al (2019), and Coelho and Umen (2021). In addition, several experiments on parthenogenesis (Tai and Fang, 1977;Fang et al, 1978;Motomura, 1991;Dai et al, 1993;Lewis et al, 1993) pointed out that parthenogenetic sporophytes which derived from female gametophytes via apomixis or apogamy could grow to maturity.…”

Section: Introductionmentioning

confidence: 84%

Discerning the Putative U and V Chromosomes of Saccharina japonica (Phaeophyta) by Cytogenetic Mapping of Sex-Linked Molecular Markers

Liu

et al. 2022

Front. Mar. Sci.

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Saccharina japonica, an importantly industrial species in brown seaweeds, has a typical alternate life history of heteromorphic generations and UV sex determination system. But up to now, the sex chromosomes, U and V, in this kelp remain to be evidenced cytologically. In the present study, the female-linked (SJ-f_000170 and MSj68-58-2) and male-linked (SJ-13_001840 and MSj68-16-2) molecular markers developed on the basis of Ectocarpus sex-determining regions (SDRs) were selected after PCR amplification and Southern blotting analysis. Mono-color fluorescence in situ hybridization (FISH) to the kelp metaphase chromosomes with each of these confirmed sex-linked markers as a probe indicated that the hybridization signals were confined to either female or male gametophytes exclusively. The shape and size of hybridized chromosomes and the relative location of these sex-linked markers on them suggested that the marked chromosomes in a sex were the same, which was further confirmed by dual-color FISH observations. SJ-f_000170 and SJ-13_001840, corresponding to each sex, were therefore used to map the sporophyte metaphase chromosomes by dual-color FISH technique, and they were hybridized on different chromosomes as expected. The sporophyte metaphase chromosomes as hybridized by SJ-f_000170 and SJ-13_001840 resembled those in either female or male gametophytes, suggesting that they were the putative U and V, respectively, chromosomes in S. japonica. To further demonstrate the reliability of this inference, genomic information of the screened bacterial artificial chromosome (BAC) clones carrying two female-linked markers, for example, from the constructed BAC libraries of the kelp female gametophytes was provided. The insert sequencing of two selected BAC clones revealed that repetitive elements were rich whereas gene density was poor, which was characterized as non-recombining SDR sequences in brown seaweed Ectocarpus sp. and liverwort Marchantia polymorpha. The present study laid a solid foundation for unveiling the mystery of S. japonica sex chromosomes.

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Switching it up: algal insights into sexual transitions

Cited by 14 publications

References 69 publications

Origin and evolutionary trajectories of brown algal sex chromosomes

Origin and evolutionary trajectories of brown algal sex chromosomes

HAP2-Mediated Gamete Fusion: Lessons From the World of Unicellular Eukaryotes

Discerning the Putative U and V Chromosomes of Saccharina japonica (Phaeophyta) by Cytogenetic Mapping of Sex-Linked Molecular Markers

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