The Mexican Tetra, Astyanax mexicanus, as a Model System in Cell and Developmental Biology.

Our understanding of cell and developmental biology has been greatly aided by a focus on a small number of model organisms. However, we are now in an era where techniques to investigate gene function can be applied across phyla, allowing scientists to explore the diversity and flexibility of developmental mechanisms and gain a deeper understanding of life. Researchers comparing the eyeless cave-adapted Mexican tetra, , with its river-dwelling counterparts are revealing how the development of the eye, pigment, brain, cranium, blood, and digestive system evolves as animals adapt to new environments. Breakthroughs in our understanding of the genetic and developmental basis of regressive and constructive trait evolution have come from research. They include understanding the types of mutations that alter traits, which cellular and developmental processes they affect, and how they lead to pleiotropy. We review recent progress in the field and highlight areas for future investigations that include evolution of sex differentiation, neural crest development, and metabolic regulation of embryogenesis. Expected final online publication date for the , Volume 39 is October 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.