Engineering life in synthetic systems

ABSTRACT The second EMBO-EMBL Symposium ‘Synthetic Morphogenesis: From Gene Circuits to Tissue Architecture’ was held virtually in March 2021, with participants from all over the world joining from the comfort of their sofas to discuss synthetic morphogenesis at large. Leading scientists from a range of disciplines, including developmental biology, physics, chemistry and computer science, covered a gamut of topics from the principles of cell and tissue organization, patterning and gene regulatory networks, to synthetic approaches for exploring evolutionary and developmental biology principles. Here, we describe some of the high points.

Embryological development of the freshwater crab Esanthelphusa nani (Naiyanetr, 1984) (Brachyura: Gecarcinucidae) using confocal laser scanning microscopy

We investigated the embryological development of Esanthelphusa nani (Naiyanetr, 1984), a common rice-field crab in northern Thailand, using confocal laser scanning microscopy. The development of E. nani can be completed in eggs within 12 d resulting in a hatchling stage corresponding to the megalopa stage. Pre-organogenetic stages were characterized by a superficial cleavage, including egg cleavage, egg blastula, and egg gastrula. Organogenesis stages were identified by the appearances of appendages and was divided into egg nauplius, egg zoea, and egg megalopa. Crabs metamorphose to juveniles after hatching. By providing new comparative data, our study shed some new light on the relationship between environment, phylogeny, and development, opening a potential area of research from the perspective of ecological, evolutionary, and developmental biology.

Individual and collective behaviour in cellular slime mould development: contributions of John Bonner (1920-2019)

John Bonner used the cellular slime moulds to address issues that lie at the heart of evolutionary and developmental biology. He did so mostly by combining acute observation and a knack for asking the right questions with the methods of classical embryology. The present paper focusses on his contributions to understanding two phenomena that are characteristic of development in general: chemotaxis of single cells to an external attractant, and spatial patterning and proportioning of cell types in the multicellular aggregate. Brief mention is also made of other areas of slime mould biology where he made significant inputs. He saw cellular slime moulds as exemplars of development and worthy of study in their own right. His ideas continue to inspire researchers.

Integrating Fossils, Natural Selection & Molecular Genetics: A Structured Inquiry-Based Evolution Lab

This structured set of lab activities allows students to explore the evolution of pelvic spine reduction in stickleback fish. The exercise draws upon the field of evolutionary and developmental biology (evo-devo) and information presented in the HHMI Holiday Lecture entitled “Fossils, Genes, and Embryos.” Students analyze fossil data from a rich stickleback deposit in Nevada, documenting the evolution of pelvic spine reduction in a preserved population, and then use Hardy-Weinberg analysis to explore the role of natural selection in this type of evolutionary event. Finally, students use molecular genetics and polymerase chain reaction to uncover the evolutionary role of gene switches in pelvic spine reduction. Collectively, the lab activities explore a specific evolutionary event from the combined perspectives of fossil evidence, natural selection, and molecular genetics. The lab also serves as a good introduction to the concepts of gene switches and evo-devo.