Reflections upon a new definition of life

Embryonic development grand challenge: crosslinking advances

Research on embryonic development is entering into a new era. As a traditionally descriptive discipline within anatomy, embryologists have formed international consortia and digitized important histological collections for preservation and open access. Embryonic development has recently received a wider attention in context with temporo-spatial transcriptomics at single cell level. These can be expected to fuel the realization of the transdisciplinary significance of efforts to decipher embryonic development. Addressing its complexities encompasses a wealth of challenges that intersect across the domains of science, society, and politics underlining its outstanding importance as well as its inherently interdisciplinary nature. The challenges of this field are by no means confined to understanding the intricate biological mechanisms but also have humanitarian implications. To fully appreciate the mechanisms underlying human development, principles of embryogenesis have predominantly been analyzed employing animal models which allow us to broaden our view on developmental processes. As a result of recent pioneering work and technical progress centered around stem cell-based 3D approaches, we are entering into a historical new phase of learning about mammalian embryonic development. In vertebrates, a growing concern now focuses the reduction of animal experimentation. This perspective article outlines the major challenges in this amazing field that offer an enormous potential for basic biomedical sciences as well as related translational approaches if they are tackled in a multidisciplinary discourse.

The Lithbea Domain

The tree of life is the evolutionary metaphor for the past and present connections of all cellular organisms. Today, to speak of biodiversity is not only to speak of archaea, bacteria, and eukaryotes, but they should also consider the "new biodiversity" that includes viruses and synthetic organisms, which represent the new forms of life created in laboratories. There is even a third group of artificial entities that, although not living systems, pretend to imitate the living. To embrace and organize all this new biodiversity, I propose the creation of a new domain, with the name Lithbea (from life-on-the-border entites) The criteria for inclusion as members of Lithbea are: i) the acellular nature of the living system, ii) its origin in laboratory manipulation, iii) showing new biological traits, iv) the presence of exogenous genetic elements, v) artificial or inorganic nature. Within Lithbea there are two subdomains: Virworld (from virus world) which includes all viruses, regarded as lifeless living systems, and classified according to the International Committee on Taxonomy of Viruses (ICTV), and ii) Humade (from human-made) which includes all synthetic organisms and artificial entities. The relationships of Lithbea members to the three classical woesian domains and their implications are briefly discussed.