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QUESTIONS. "The first multicellular animals and plants belonging to the eukaryote terminal crown group are believed to have appeared around 0.7 to more than one billion years ago. Were they the first living beings whose cells were endowed with the capacity to self-destruct? Were effectors of cell suicide already present and operational in the first multicellular animals and plants, or were they selected later from other ancestral signaling pathways? When did the capacity to self-destruct initially appear?" http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

SELF-DESTRUCTION KEY TO EVOLUTION. ""The observation that plant cells share with animal cells the capacity to self-destruct in response to environmental changes and cell signaling has reinforced the idea that programmed cell death may have played an essential role in the development, survival and evolution of most, if not all, multicellular organisms." http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

CONSERVATION AND DIVERSITY. "As frequently occurs during evolution, however, this striking conservation in both sequences and functional properties has been associated with a great level of diversification." http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

FAMILIES OF GENES. "During the last nine years, homologues of genes involved in the regulation of programmed cell death in Caenorhabditis elegans have been identified in sponge, in Hydra vulgaris, in the fruitfly Drosophila melanogaster, in zebrafish, in mice and in humans." http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

GENETIC ORIGIN. "The identification of a regulated cell death program inducing an apoptotic phenotype in nine different single-celled eukaryote organisms that belong to four diverging branches of the eukaryote phylogenic tree provides a paradigm for a widespread role for programmed cell death in the control of cell survival, and raises the question of the origin and nature of the genes that may be involved in the execution and regulation of such a process." http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

TRIGGERS. "Programmed cell death induction may depend essentially on cell-lineage information, such as in the nematode Caenorhabditis elegans, on the activation of gene transcription, such as in the fruitfly Drosophila melanogaster, or, in a more stochastic way, on a combination of cell-lineage information, intercellular signaling, transcription factor activation and cytoplasmic second messengers, such as in mammals." http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

WIDE AND OLD. "Various forms of regulated programmed cell death have now been described in nine species of unicellular eukaryotes, belonging to four different branches whose phylogenic divergence is believed to range from around two to one billion years ago." http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

EXTERNAL SIGNALS. "In all cases that have been studied to date, programmed cell death is regulated by signals provided by other cells, either in the form of cell-lineage information, of soluble mediators, or of cell-to-cell contacts." http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

SINGLE OR MULTIPLE? "Did this frontier arise after the initial three billion years of evolution of single-celled organisms, at the time at which the first multicellular organisms emerged, or did this frontier arise in the kingdom of the single-celled organism, prior to the emergence of multicellular organisms?" http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn

CONSERVED. "Programmed cell death has been found to operate in all multicellular animals studied so far, including cnidaria, nematodes, insects, amphibians, birds and mammals. The evolutionary conservation of programmed cell death in the animal kingdom does not only involve its existence and role, but extends to some central aspects of its genetic control, and to important aspects of its most frequent phenotype, apoptosis." http://www.nature.com/cdd/journal/v9/n4/full/4400950a.html View in LinkedIn