Ordovician origin and subsequent diversification of the brown algae

Choi, Seok-Wan; Graf, Louis; Choi, Ji Won; Jo, Jihoon; Boo, Ga Hun; Kawai, Hiroshi; Choi, Chang Geun; Xiao, Shuhai; Knoll, Andrew H.; Andersen, Robert A.; Yoon, Hwan Su

doi:10.1016/j.cub.2023.12.069

Cited by 16 publications

(9 citation statements)

References 100 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To identify sex-determining genes, we examined genomes spanning the brown algal phylogeny and representing more than 400 million years of evolution ( 33 ). A single gene was V-limited in all studied species ( 34 ).…”

Section: Identification Of a Candidate Male-determining Genementioning

confidence: 99%

“…HMG-sex is a V-linked gene across all examined brown algae with separate sexes ( 34 ), suggesting a conserved function in sex determination. To test this hypothesis, we generated HMG-sex KO mutants in the kelp Laminaria digitata , which diverged from Ectocarpus more than 100 million years ago ( 33 ). Sexual dimorphism in kelps is substantially more conspicuous than in Ectocarpus ( 55 ), providing an opportunity to investigate the role of HMG-sex in an organism with strong gametophyte sexual dimorphism.…”

Section: Hmg-sex Is Required For Sex Determination In Kelpsmentioning

confidence: 99%

See 1 more Smart Citation

Repeated co-option of HMG-box genes for sex determination in brown algae and animals

Luthringer,

Raphalen,

Guerra

et al. 2024

Science

View full text Add to dashboard Cite

In many eukaryotes, genetic sex determination is not governed by XX/XY or ZW/ZZ systems but by a specialized region on the poorly studied U (female) or V (male) sex chromosomes. Previous studies have hinted at the existence of a dominant male-sex factor on the V chromosome in brown algae, a group of multicellular eukaryotes distantly related to animals and plants. The nature of this factor has remained elusive. Here, we demonstrate that an HMG-box gene acts as the male-determining factor in brown algae, mirroring the role HMG-box genes play in sex determination in animals. Over a billion-year evolutionary timeline, these lineages have independently co-opted the HMG box for male determination, representing a paradigm for evolution’s ability to recurrently use the same genetic “toolkit” to accomplish similar tasks.

show abstract

Section: Identification Of a Candidate Male-determining Genementioning

confidence: 99%

Section: Hmg-sex Is Required For Sex Determination In Kelpsmentioning

confidence: 99%

Repeated co-option of HMG-box genes for sex determination in brown algae and animals

Luthringer,

Raphalen,

Guerra

et al. 2024

Science

View full text Add to dashboard Cite

show abstract

“…It remains to be determined what mechanisms are responsible for eliminating and fragmenting inserted phaeoviruses. The identification of large-scale viral genome insertion events over such a long timescale (at least 450 My 69 ) suggests that NCVs may have had a major impact on the evolution of brown algal genomes throughout the emergence of the lineage, making this a truly unique model system to investigate the impact of genomic exchanges on genome evolution.…”

Section: Resultsmentioning

confidence: 99%

“…Since the establishment of the brown algal lineage, approximately 450 Mya 69 , the Phaeophyceae have diversified and adapted to multiple niches in predominantly coastal, marine environments. This diversification has resulted in organisms with a broad range of morphological complexity ranging from filamentous to complex parenchymatous thalli, with the more complex thalli containing a greater number of different cell types (Figures 1 and S9A).…”

Section: Resultsmentioning

confidence: 99%

Evolutionary genomics of the emergence of brown algae as key components of coastal ecosystems

Denoeud,

Godfroy,

Cruaud

et al. 2024

Preprint

Self Cite

View full text Add to dashboard Cite

SUMMARYBrown seaweeds are keystone species of coastal ecosystems, often forming extensive underwater forests, that are under considerable threat from climate change. Despite their ecological and evolutionary importance, this phylogenetic group, which is very distantly related to animals and land plants, is still poorly characterised at the genome level. Here we analyse 60 new genomes that include species from all the major brown algal orders. Comparative analysis of these genomes indicated the occurrence of several major events coinciding approximately with the emergence of the brown algal lineage. These included marked gain of new orthologous gene families, enhanced protein domain rearrangement, horizontal gene transfer events and the acquisition of novel signalling molecules and metabolic pathways. The latter include enzymes implicated in processes emblematic of the brown algae such as biosynthesis of the alginate-based extracellular matrix, and halogen and phlorotannin biosynthesis. These early genomic innovations enabled the adaptation of brown algae to their intertidal habitats. The subsequent diversification of the brown algal orders tended to involve loss of gene families, and genomic features were identified that correlated with the emergence of differences in life cycle strategy, flagellar structure and halogen metabolism. We show that integration of large viral genomes has had a significant impact on brown algal genome content and propose that this process has persisted throughout the evolutionary history of the lineage. Finally, analysis of microevolutionary patterns within the genusEctocarpusindicated that deep gene flow between species may be an important factor in genome evolution on more recent timescales.

show abstract

“…Remarkably, MBGs of brown algae with XX/XY systems in the order Fucales do not experience high turnover rates, but instead reveal remarkable conservation of bias and expression levels 53 . It is possible that the young age of the XX/XY system of the Fucales (65 Mya) 28,54 , compared to the very old U/V system (> 450 Mya) 28,54 , underlies these differences.…”

Section: Discussionmentioning

confidence: 99%

Developmental pathways underlying sexual differentiation in a U/V sex chromosome system

Liesner,

Cossard,

Zheng

et al. 2024

Preprint

View full text Add to dashboard Cite

In many multicellular organisms, male and female developmental fates are not determined by the classic XX/XY or ZW/ZZ systems but rather by a third type of sex chromosomes, the U/V sex chromosomes. In U/V systems, sex is expressed in the haploid phase, with U chromosomes confined to females and V chromosomes to males. Here, we explore several male, female and partially sex-reversed male lines of a giant kelp with a U/V system, to decipher the role of U/V sex chromosomes and autosomes in the initiation of male versus female developmental programs. Using comparative transcriptomics and experimental approaches, we identify a small set of genes located on the V- and U sex chromosomes that play a role in triggering the male versus female developmental programs, and we uncover a subset of autosomal effector genes. We describe the transcriptomic pathways underlying sexual differentiation and show that male, but not female, developmental fate involves large-scale transcriptome reorganization with pervasive enrichment in regulatory genes affecting the expression of more than half of the giant kelp genome. Furthermore, male-biased genes are more species-specific and exhibit faster evolutionary rates than unbiased genes, whereas genes underlying female developmental fate are more evolutionary conserved. Our observations imply that a female-like phenotype is the 'ground state' of the giant kelp morphology, which is complemented by the presence of a U-chromosome, but overridden by a dominant male developmental program in the presence of a V-chromosome.

show abstract

Ordovician origin and subsequent diversification of the brown algae

Cited by 16 publications

References 100 publications

Repeated co-option of HMG-box genes for sex determination in brown algae and animals

Repeated co-option of HMG-box genes for sex determination in brown algae and animals

Evolutionary genomics of the emergence of brown algae as key components of coastal ecosystems

Developmental pathways underlying sexual differentiation in a U/V sex chromosome system

Contact Info

Product

Resources

About