LivingMatterRGBtrzEarly in The Century of Biology, the life sciences are experimenting profound technological transformations that might have dramatical social and economic implications. One of the challenges of this period is to work out a proper definition for living matter. This is an interdisciplinary quest: contributions from disciplines as diverse as astrobiology and bacteriology will have to be combined with ongoing research in genetics and embryology.

Computer Science contributes to this effort in many ways, most of them subscribed to the Bioinformatics field. Computer power, both hardware and software, is dedicated to unveiling obscure secrets like the genomic structure and function, the folding of proteins, and the programmed development of a multicellular body. A more theoretical line of work has something to say in this quest for the basis of life. Artificial Life searches for mathematical models that encapsulate fundamental properties of the living phenomena. This discipline aims to simulate processes of the carbon-based life we find around us, as well as depicting life as-it-could-be.

 

 

This being leaves behind a similar structure to the initial egg, and the short ends in exactly the reversed way that it started, suddenly closing an strange loop that brings in the common paradox of tangled hierarchies of living systems.

Similar experiments have been carried out, where physical structures evolve as to develop organs that accommodate the impact in a landing test. The animation shows first the best fitted structure, that makes it pointing its sharp pyramidal top in the direction of the surface to avoid deformation and displacement from the contact point, and finally stands on the ground. Other (not so fitted) structures land at the end of the animation.  The one at the left has been obtained with an explicit coding strategy, basically different from the first one, based on implicit encoding and a developmental program.

 

 

We also look for new insights in the multiple questions posed by multicellular forms of life, particularly the development of fully-fledged bodies from undifferenciated eggs. The triumphalist point of view established in the last decades of the last century, almost exclusively based on the central dogma of molecullar biology, is regarded to be too reductionist: vast efforts are devoted to bind specific development events with specific genetic switches. In our approach, we pay more attention to the way the genetic system modifies (and is modified by) the embryo's physical characteristics.

 An example is provided in the next animation. It shows a simulated development, starting with a cell egg which repeatedly cleaves.

 

 

Each cleavage is biased, so one of the daugthers is differentially bigger than her sister. In the 128-cell stage we can see morphogenesis, i.e., forms arising from the undifferentiated egg (the cells are coloured at the 8-cell stage to underscore the effect). The point here is that genes only control cleavage asymmetry and general physical conditions of the cell material (moreover, these parameters are not changed throughout this simulation), so forms emerging in the embryo can be described poorly  by genetics alone: it is needed to integrate physical medium conditions and genetics in order to explain development in comprehensible terms.