Selecting for multicellularity in the unicellular alga Chlamydomonas reinhardtii
Notice bibliographique
Résumé

 
 
 Background: Researchers have recently begun experimentally exploring the origins of multicellularity (4-6). Their studies have found that the transition to a multicellular state may have been surprisingly simple, considering its profound implications for the history of life (3). This study experimentally selected for multicellularity in the unicellular biflagellated alga Chlamydomonas reinhardtii. This organism is especially interesting because it is basal to the Volvocaceae—a family of biflagellates whose evolutionary transition from unicellular organisms to complex forms have been meticulously characterized (2). The present study aimed to recreate the early stages of this transition, starting from incomplete cytokinesis after cell division.
 Methods: The procedure was modeled loosely on the experiment performed by Ratcliff et al. (4) in which the authors successfully selected for multicellular Saccharomyces Cerevisiae—unicellular baker’s yeast. Three experimental replicates and one control for nine strains of C. reinhardtii were cultured in round-bottom vials in shaking incubators. Prior to each transfer (every 3-4 days), each culture was slowly mixed, and selection lines were then gently and briefly centrifuged. This applied a selection pressure which rendered heavier (clustered) cells more fit. The very bottom ~2% of the tubes’ contents was transferred, and cell cultures were examined for multicellularity.
 Results: Six of nine lines of C. reinhardtii demonstrated an increased frequency of C. reinhardtii existing in a two- to four-celled state (the paired cell state accounted for 88% of these clusters)—consistent with the first step toward multicellularity as outlined by Kirk (2). A close study of cell division in the line which exhibited the strongest shift towards the multicellular phenotype suggests that true multicellularity began to evolve in this experiment. A multicellular phenotype did not become fixed in any population.
 Conclusion: Our findings suggest that an artificial selection pressure is capable of inducing the evolution of multicellularity. Expanding upon this study could help us understand the mechanisms underlying the evolution of multicellularity.
 Limitations: Sporadic data, possibly the result of difficulties in the procedure, prevented us from rigorously examining the effect of selection through time, limiting our ability to describe the evolutionary response. In addition, the study of individual cells, due to its time-consuming nature, was limited to one replicate of one line exhibiting a pronounced multicellular response. Thorough replication would be required before drawing a strong conclusion from this assay.
 
 
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,017 | 0,003 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,002 |
| Études des sciences et des technologies | 0,005 | 0,001 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,002 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».