Symbiosis

We have three main areas of interest in symbiosis: the origin of plastids, the function of mitochondria, and symbiosis between Symbiodinium dinoflagellates and corals or anemones.

In conjunction with Peter Beech, we discovered that some mitochondria use the bacterial division protein FtsZ to divide, reinforcing the theory of endosymbiotic origin of mitochondria.  More recently we are interested in mitochondria as drug targets in malaria, particularly for the management of antimalarial drug resistance.

The McFadden lab has investigated the origin of plastids in a group of algae known as chlorarachniophytes, and we showed that chlorarachniophytes stole their plastids from another eukaryote (a green alga) by cannibalizing it for parts.  We sequenced the genetic residue of the enslaved green alga’s nucleus to understand this process.  We found a nucleus so tiny that it is barely recognisable.  Three miniature chromosomes, complete with telomeres, encode a mere 340 genes.  Curiously, this compact little genome is replete with introns; a staggering 852 introns interrupt the protein genes.  Ranging in size from only 19-21 base pairs, these are the smallest known introns, much in keeping with the overall pattern of genetic miniaturization after enslavement.  We call it Bonsai genomics!

A new project in conjunction with Prof Madeleine van Oppen is looking at how dinoflagellate symbionts are recruited and integrated by corals.  We use an anemone model to study this intimate symbiotic relationship, which is a basis for coral reefs.