Paramecium tetraurelia autogamy series 1

In the ciliate Paramecium tetraurelia, autogamy is a self-fertilization process, during which the zygotic nucleus results from the fusion of two identical gametic nuclei. This phenomenon occurs in response to starvation. It starts with meiosis of the germline nuclei (micronuclei or MIC) and fragmentation of the parental somatic nucleus (macronucleus or MAC). This is followed by mitotic division of one haploid nucleus issued from meiosis to yield two identical gametic nuclei, then karyogamy takes place, followed by mitosis of zygotic nucleus and differentiation of new MICs and MACs from the resulting copies of the zygotic nucleus. Within the developing new MACs, developmentally programmed DNA amplification and extensive genome rearrangements (precise excision of short non coding Internal Eliminated Sequences and chromosome fragmentation associated with the imprecise elimination of repetitive DNA) give rise to the highly polyploid somatic genome. To gain further insight into the complex regulation of these successive steps, we used whole genome microarrays to study the different gene networks that become activated throughout autogamy. Total RNA was extracted before the begining of autogamy (reference sample) and at 5 different time points during the process of autogamy. There are two biological replicates for each point.