Angiosperm plants imprint some genes during endosperm development, and although some components of the FIS complex (mea, fis2 and fie; related to the Polycomb group of chromatin remodelling factors) have been implicated in mediating this phenomenon, the actual role of imprinting in seed development remains unclear. In this paper, Nowack et al. generated Arabidopsis seeds whose endosperm is uniparental (maternal: the CDKA;1 mutant tagged with a YFP reporter), and using mutants for the FIS- class genes, they showed that uniparental seeds can develop without a paternal genome contribution if they lack of any of the functional FIS- class genes, meaning that imprinting in developing seeds can be bypassed. This investigation brings new insights for the evolutionary role of the endosperm, in contrast to the gymnosperm development, where descendants are produced by a single fertilization.
Nowack MK. et al. 2007. Nature 447: 312-316
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