Project description:As the only surviving lineages of jawless fishes, hagfishes and lampreys provide a critical window into early vertebrate evolution. Here, we investigate the complex history, timing, and functional role of genome-wide duplications in vertebrates in the light of a chromosome-scale genome of the brown hagfish Eptatretus atami. Using robust chromosome-scale (paralogon-based) phylogenetic methods, we confirm the monophyly of cyclostomes, document an auto-tetraploidization (1RV) that predated the origin of crown group vertebrates ~517 Mya, and establish the timing of subsequent independent duplications in the gnathostome and cyclostome lineages. Some 1RV gene duplications can be linked to key vertebrate innovations, suggesting that this early genomewide event contributed to the emergence of pan-vertebrate features such as neural crest. The hagfish karyotype is derived by numerous fusions relative to the ancestral cyclostome arrangement preserved by lampreys. These genomic changes were accompanied by the loss of genes essential for organ systems (eyes, osteoclast) that are absent in hagfish, accounting in part for the simplification of the hagfish body plan; other gene family expansions account for hagfishes’ capacity to produce slime. Finally, we characterise programmed DNA elimination in somatic cells of hagfish, identifying protein-coding and repetitive elements that are deleted during development. As in lampreys, the elimination of these genes provides a mechanism for resolving genetic conflict between soma and germline by repressing germline/pluripotency functions. Reconstruction of the early genomic history of vertebrates provides a framework for further exploration of vertebrate novelties.
Project description:Proteomic analysis of six tissues (liver, kidney, blubber, brain, muscle, skin) provided experimental confirmation of 10,402 proteins from 4,711 protein groups, almost 1/3 of the possible predicted proteins in the Atlantic bottlenose dolphin (Tursiops truncatus) NCBI annotation (release 101), which is based on the recently completed NIST Tur_tru v1 genome assembly.
Project description:Experiment with 2 conditions: - Contactless : A. glutinosa alone in nitrogen-free culture medium during 2 days (reference condition). - Indirect : A. glutinosa in nitrogen-free culture medium containing the Frankia bacterium confined in a dialysis tube during 2 days.
Project description:Experiment with 2 conditions: - BAP-PCM : A. glutinosa alone in nitrogen-free culture medium plus frankialess culture medium during 2 days (reference condition). - CN BAP-PCM : A. glutinosa in nitrogen-free culture medium with Frankia culture supernatant during 2 days.
