The African turquoise killifish: A research organism to study vertebrate aging and diapause.

The African turquoise killifish has recently gained significant traction as a new research organism in the aging field. Our understanding of aging has strongly benefited from canonical research organisms-yeast, C. elegans, Drosophila, zebrafish, and mice. Many characteristics that are essential to understand aging-for example, the adaptive immune system or the hypothalamo-pituitary axis-are only present in vertebrates (zebrafish and mice). However, zebrafish and mice live more than 3 years and their relatively long lifespans are not compatible with high-throughput studies. Therefore, the turquoise killifish, a vertebrate with a naturally compressed lifespan of only 4-6 months, fills an essential gap to understand aging. With a recently developed genomic and genetic toolkit, the turquoise killifish not only provides practical advantages for lifespan and longitudinal experiments, but also allows more systematic characterizations of the interplay between genetics and environment during vertebrate aging. Interestingly, the turquoise killifish can also enter a long-term dormant state during development called diapause. Killifish embryos in diapause already have some organs and tissues, and they can last in this state for years, exhibiting exceptional resistance to stress and to damages due to the passage of time. Understanding the diapause state could give new insights into strategies to prevent the damage caused by aging and to better preserve organs, tissues, and cells. Thus, the African turquoise killifish brings two interesting aspects to the aging field-a compressed lifespan and a long-term resistant diapause state, both of which should spark new discoveries in the field.