Beyond mere memory, anniversaries of positive events can be a source of great enjoyment when most of the people who contributed to them are able to participate at the celebrations. Such was the case on November 9th, 2010 within the history-filled, prestigious premises of the Institut de France in Paris. This date was chosen to celebrate the tenth anniversary of the Génolevures Consortium, a scientific initiative devoted to the exploration of many yeast genomes as a means to better understand the origin, evolution and biological diversity of these important unicellular fungi, and to provide an integrated wealth of novel genome sequence data prone to accelerate subsequent investigations. Although the beginning of this endeavor, as often in such cases, is difficult to date with precision, ten years have now passed since the neologism “Génolevures” first appeared in the scientific literature¹ and since the CNRS decided to create a Groupement de Recherche (GDR 2354) devoted to the then emerging field of comparative and evolutionary genomics of yeasts. Considerable progress has been made during this period, along with the astonishing acceleration of Genomics in general, impacting all aspects of Biology. To the risk of appearing presumptuous, we like to believe that our little yeasts, with their compact genomes so exquisitely amenable to experimental analyses as well as to extensive genomic comparisons, have contributed their share to our present understanding of eukaryotic genomes and will continue to do so.

The scientific program of our one-day meeting “Dix ans d’exploration génomique chez les eucaryotes : la stratégie et les avancées de Génolevures” (10 years of genomic exploration of eukaryotes: strategy and progress of Génolevures) was the place to discuss recent aspects of yeast genomics by some members of the Consortium, but it was also the occasion to welcome other colleagues, from France or abroad, sharing common scientific interests. Presenting their results, tools, ideas or hypotheses with remarkable scientific insights, they all contributed to the success of this anniversary and its very friendly atmosphere. I beg them to accept here my deepest and most sincere acknowledgements.

This special issue of the Comptes Rendus Biologies devoted to yeast genomics presents a series of 15 short scientific articles prepared by participants to our anniversary meeting. Altogether, they offer views of various scientific issues touched upon by comparative genomics of yeasts over the last 10 years. I thank the authors for their timely and most interesting contributions, as well as the many anonymous referees that I have solicited to give their expert opinion on the content of these articles and who, despite busy agendas, have all accepted this additional task and performed it so promptly. Given space limits, not all topics could obviously be comprehensively covered in this issue, but I believe that it provides a scientifically up-to-date and reasonably equilibrated image of the field, hopefully accessible to non-specialized readership.

After a brief historical chapter summarizing the 10 years of the Génolevures Consortium (paper 1, Souciet), the volume starts with a precise outline of the Génolevures database (paper 2, Martin et al.), a most important tool for any development of genomics, and then discusses yeast taxonomy (paper 3, Casarégola et al.), another critical aspect for comparative genomics complicated by the impact that interspecies hybridization and loss of heterozygosity have on phylogenetic reconstructions. In paper 4, Knop offers us his original views on the link between morphology and reproductive properties, comparing mononucleated cells, a common signature of yeasts, with the polynucleated syncytia of other fungi or also some yeasts. These are central concepts to introduce new graduate students, and others, to cellular decision-making processes and to their reproductive and evolutionary importance. In paper 5, Santos et al. review the last ideas about the unique genetic code alteration that occurred few hundred million years ago in the ancestry of a now large yeast lineage. The leucine/serine ambiguity creates heterogeneous populations of proteins in the cells having important biological consequences. With their small genomes, yeasts were also at the forefront of the emerging science of population genomics, even before the advent of novel sequencing technologies, and Liti and Schacherer (paper 6) review pioneer results on the genetic diversity in two related species, Saccharomyces cerevisiae and S. paradoxus, and how these data are pertinent to our understanding of the structure and evolution of natural populations.

The volume then continues with the problem of dating genomic changes and rates of genome rearrangements during evolution. Considering mutational rates in clonal populations, Rolland and Dujon (paper 7) propose an original method to calibrate short-term clocks. They then compare chromosomal rearrangements at various evolutionary distances for both yeasts and insects while, separately, Drillon and Fischer (paper 8) compare rates of genome rearrangements in yeasts and vertebrates. Interestingly, in both cases, yeast genomes appear more stable in synteny conservation than animal ones for similar levels of sequence divergence. Or put in the other way, yeast sequences are much more diverged than animal ones for similar degrees of synteny conservation. Against these clocks, Despons et al. (paper 9) describe the plastic chromosomal organization offered by the dynamics of tandem-gene arrays, suggesting their role in rapid adaptation rather than long-term evolution.

Whatever the depth of analysis, understanding genomes cannot be complete without studying RNAs. In paper 10, Perez-Ortin and Pelechano discuss most recent methods to measure transcription and degradation of mRNA in yeasts. They apply them to monitor mRNA turnover in S. cerevisiae, a very important aspect to approach gene expression regulation. Lelandais et al. (paper 11) further show how transcriptomic networks can be compared between yeast species, opening the very promising route of comparative transcriptomics, and Neuvéglise et al. (paper 12) review our knowledge about the rare but functionally important spliceosomal introns in budding yeasts. Despite their fundamental importance for gene expression, RNA molecules are, however, not limited to this role in living cells, and Cruz and Westhof (paper 13) summarize the methods used to identify genes for non-coding RNA in sequences, a frequently overlooked aspect of genome annotations. They compare results of homology-search and de novo pipelines applied to yeast genomes and conclude about the necessity for automatic search of ncRNAs in all multi-genome sequencing projects. But RNA-mediated mechanisms also play some role in genome dynamics through evolved transposable elements. Summarizing our knowledge of such elements in yeast genomes, Bleykasten-Grosshans and Neuvéglise (paper 14) show their diversity, although class I elements with LTR largely prevails over other types of elements, and their varying presence/absence between lineages.

Finally, reviews on yeast genomes would not be complete without a special mention of the species used for fermentation. After all, without the fermentations, our attention might not have been focused on yeasts as model systems for basic biological studies, and S. cerevisiae would probably not have been the first eukaryotic genome sequenced². However, genomics, in turn, has now considerably accelerated our characterization of the yeast species and strains used in fermentations, as remarkably illustrated by Dequin and Casarégola (paper 15) to conclude this volume.

Reading these exciting articles, one hardly imagines that only 10 years ago, most of their scientific content was unknown. Happy anniversary Génolevures!