Because hydrothermal vent systems are hypothesized to be extreme
environments that have been present since the early history of the
planet, understanding the ability of organismal lineages to adapt
and thrive in such environments is of interest to evolutionary biologists.
The lab has been focusing on the reconstructing the phylogenetic
history of key taxonomic groups to understand the origins of vent
fauna and how taxa in vent environments speciate and maintain genetic
communication. The primary taxon of interest has been the siboglinid
tube-worms. (Siboglids were formerly recognized as vestimentiferans
and pogonophorans.) These gutless worms are nourished by endosymbiotic
bacteria.
Using a multigene approach, we
have been exploring the relationship of hydrothermal vent tubeworms
to tubeworms from cold seeps, and their more distant relatives (the
frenulate breadworms found on rotting wood, continental margins, or
sedimented habitats). In particular, we are exploring the hypothesis
that all vent dwelling siboglinids arose from a common ancestor (as
suggested by the mitochondrial cytochrome oxidase I gene). Our data
also suggests that there may be an evolutionary trend in habitat preference
towards increasingly reducing environments. This trend may have been
driven by the endosymbiotic bacteria the worms use to harness energy.
In addition to the phylogenetic
work, we have been developing molecular markers for more rapidly evolving
loci. The use of these markers will be instrumental in understanding
genetic variation and structure on a population level. Amplified Fragment
Length Polymorphsms or (AFLPs) are a promising DNA fingerprinting
technique that samples hundreds of loci simultaneously.