Synthetic Biology is redesigning the boundaries in between kingdoms. Darwinian evolution is not the only force driving the emergence of new life forms anymore. Rational design of existing living organisms is changing our relationship with the living to a point some people are re-thinking the tree of life.
-What’s a Kingdom?-
In biology, kingdom (Latin: regnum, pl. regna) is a taxonomic rank, which is either the highest rank or in the more recent three-domain system, the rank below domain. Kingdoms are divided into smaller groups called phyla (in zoology) or divisions in botany. The complete sequence of ranks is life, domain, kingdom, phylum, class, order, family, genus, and species. (Thanks wiki)
This classification changed a lot over time and is a good image of our understanding of what life is and how life forms are evolutionary interconnected. The clues to set those boundaries were first morphological but since the 70s genetics helped a lot our understanding.
The current classification from Carl Woese from the 90s uses a lot of these genetic clues, notably from the RNA 16s and is a representation of how species are linked together through evolution.
-Synthetica?-
Arguably, I would say “Synthetica” is not a new kingdom but a separate and distinct entity.
There is no evolutionary link in between those life forms and the only shared thing is the fact that they were rationally engineered.
In this vision, we would need to add a new dimension to the tree of life as Synthetica is not linked to the other kingdom through evolution but through a rational choice: “I am going to do directed evolution on this bug because it is already able to eat oil and I want to evolve the “best” bacteria to clean oil spills” or “we would like a yeast able to produce drug X, the pathway does not exist in nature but if I pick gene a from this archea and gene b from this bacteria it will work”.
Then the branches linking these life forms could reflect what kind of engineering was used, e.g. metabolic engineering, directed evolution… And the branches linked to the kingdoms what were borrowed from them.
In this sense I do prefer to think of “Synthetica” not as a “Kingdom” but as an “Ingdom”. Ing as in Ingenuity / ingenuous from the latin Ingenium (Smartness, natural capacity).
What’s a bacteria with genes from the Archea and/or the Eucarya kingdom?
How should we classify life made from scratch? (We are not there yet but lots of people are working on it)
What’s our new relationship to life?
What’s your relationship to life?
More:
- Wikipedia: Three Domain Classification
- Alexandra Daisy Ginsberg’s blog and article on the Synthetica Kingdom
