Project description:Comparative Genome Hybridization of Ectocarpus siliculosus strains 371 (freshwater ecotype), 524 (copper-tolerant strain), and 568 (female strain), as well as E. fasciculatus strain 395 against the sequenced genome strain (32).
Project description:Reference reference hybridization with Ectocarpus siliculosus (strain Es 32) genomic DNA; Quality control for submission E-TABM-766
Project description:In UV sexual systems, sex is determined during the haploid phase of the life cycle and males have a V chromosome whereas females have a U chromosome. Previous work in the model Ectocarpus revealed that the V chromosome has a dominant role in male sex determination and the female developmental program being a ‘default’ program, triggered in the absence of the male master sex determination gene(s). Here, we describe the identification of a genetically male giant kelp strain presenting phenotypic features typical of a female, despite lacking the U-specific region. The conversion to the female developmental program is however incomplete, because gametes of this feminised male are unable to produce the sperm-attracting pheromone lamoxiren. We identify the transcriptomic pathways underlying the male and female specific developmental programs and show that the phenotypic feminisation of the variant strain is associated with both feminisation and de-masculinisation of gene expression patterns. Importantly, the feminisation phenotype was associated with the dramatic downregulation of two V-specific genes including a candidate sex-determining gene on the V-specific region. Our results reveal the transcriptional changes associated with sexual differentiation in a UV system with extensive sexual dimorphism, disentangling the role of sex-linked genes and autosomal gene expression in the initiation of the male and female developmental programs. Overall, the data presented here imply that the U-specific region in the giant kelp is not required to initiate the female developmental program, but is critical to produce fully functional eggs, arguing against the idea that female is the ‘default’ sex in this species.
Project description:The aim of the experiment is to identify Ectocarpus siliculosus (strain Ec32) genes which are up- or down-regulated by auxin. RNAs were extracted from sporophytes treated with auxin NAA 5.10-6M for 30min or 3h, and labelled either with Cy3 or Cy5. Biological triplicates were performed.
Project description:The aim of this study was to analyze genome-wide patterns of histone post-translational modifications (PTMs) and nucleosome distribution during the sporophyte and gametophyte generations of the life cycle of the brown alga Ectocarpus. Analysis of the results of this experiment along with those generated by a second experiment “Genome-wide analysis of chromatin states of Ectocarpus sporophytes and gametophytes, experiment 2” indicated that the histone PTMs H3K4me2, H3K4me3, H3K9ac, H3K14ac and H3K27ac are associated with the transcriptional start sites (TSSs) of actively expressed genes, H3K36me3 preferentially marks gene bodies and is associated with gene activation, H4K20me3 marks transposons and is associated with gene repression, probably through the silencing of transposons in introns. H3K79me2 occurs in zones corresponding to about a third of the genome. These zones often span several genes and genes within H3K79me2 zones exhibit lower levels of transcript abundance.
Project description:The aim of this study was to analyze genome-wide patterns of histone post-translational modifications (PTMs) and nucleosome distribution during the sporophyte and gametophyte generations of the life cycle of the brown alga Ectocarpus. Analysis of the results of this experiment along with those generated by a second experiment “Genome-wide analysis of chromatin states of Ectocarpus sporophytes and gametophytes, experiment 1” indicated that the histone PTMs H3K4me2, H3K4me3, H3K9ac, H3K14ac and H3K27ac are associated with the transcriptional start sites (TSSs) of actively expressed genes, H3K36me3 preferentially marks gene bodies and is associated with gene activation, H4K20me3 marks transposons and is associated with gene repression, probably through the silencing of transposons in introns. H3K79me2 occurs in zones corresponding to about a third of the genome. These zones often span several genes and genes within H3K79me2 zones exhibit lower levels of transcript abundance.
Project description:The aim of this experiment was to analyse the expression of two sets of genes identified as being putatively sporophyte-specific or gametophyte-specific by a suppressive subtraction hybridisation using cDNA from immature sporophytes and immature gametophytes of the Ectocarpus strain Esil32. The expression of these genes was analysed in the sporophyte and gametophyte generations of the life cycle (again using immature algae that had not yet produces zoidangia) and in the sporophyte generation of a mutant strain, immediate upright, that exhibits gametophyte-like characteristics during the sporophyte generation.
