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M.S. Clark et al.
how this fauna adapted to the highly poisoning sulphide vent environment. In this
particular case, the respiratory pigment is able to reversibly bind sulphide onto two
distinct cysteine residues of the A2 and B2 globins (Bailly et al. 2002). Bailly et al.
(2003) demonstrated that such an ability was probably lost by positive Darwinian
selection during the course of evolution in modern annelids living in non-reducing
habitats.
There is a distinct lack of sequence data from hydrothermal species. However,
a recent effort has concentrated on the sequencing of the transcriptomes of
Bathymodiolus azoricus, Paralvinella grasslei, Alvinella pompejana and Riftia
pachyptyla) (Sanchez et al. 2007, Tanguy et al. 2008, Alvinella Consortium Project).
The first cDNA microarrays have also been developed for B. azoricus and P. grasslei
and the aim is to use these as models in order to study the response of these organisms to temperature challenges, heavy metal effects and symbiosis. A recent study
has already demonstrated that deep-sea vent mussels can endure a global depression
in gene expression associated with short-term exposures (30–120 min) to temperatures higher than 20 ◦ C, suggesting that these animals are more likely adapted to
cold temperatures (Boutet et al. 2008).
3.4.4.2 Polar Environments
Living in the cold obviously has resulted in specialist genetic adaptations, of which
there are some classic single gene investigations:
• Plasma antifreeze: this was first discovered in Antarctic fish (DeVries 1970), but
now recognised as a standard adaptation to the cold marine environment (DeVries
1982).
• Specific protein modifications resulting in increases in molecule flexibility, essential for efficient functioning in the cold (Fields and Somero 1998, Detrich et al.
1989, 1992, Fields et al. 2002,Römisch et al. 2003).
• Deletion of haemoglobin genes and the ability to produce functional erythrocytes
in the Channichthyidae (icefish) (Moylan and Sidell 2000, di Prisco et al. 2002).
• Lack of the classical heat shock response (upregulation of the inducible form of
HSP70) in a number of fish and invertebrate species (Hofmann et al. 2000, Clark
et al. 2008a, c).
This latter “adaptation” has been recently investigated via a pilot microarray analysis hybridizing RNA from the Antarctic fish Trematomus bernacchii onto an array
produced for the eurythermal goby fish Gillichthys mirabilis (Buckley and Somero
2009). In this study they showed that the Antarctic fish, although not displaying
the classical heat shock response, did indeed show enhanced expression of many
genes associated with central aspects of the evolutionary conserved cellular stress
response. Whilst this experiment used a heterologous array approach, organismspecific arrays are now becoming available for some polar terrestrial insects
(cf. Purac et al. 2008) and it is expected that this will soon also be the case with
polar marine species.
M.S. Clark et al.
how this fauna adapted to the highly poisoning sulphide vent environment. In this
particular case, the respiratory pigment is able to reversibly bind sulphide onto two
distinct cysteine residues of the A2 and B2 globins (Bailly et al. 2002). Bailly et al.
(2003) demonstrated that such an ability was probably lost by positive Darwinian
selection during the course of evolution in modern annelids living in non-reducing
habitats.
There is a distinct lack of sequence data from hydrothermal species. However,
a recent effort has concentrated on the sequencing of the transcriptomes of
Bathymodiolus azoricus, Paralvinella grasslei, Alvinella pompejana and Riftia
pachyptyla) (Sanchez et al. 2007, Tanguy et al. 2008, Alvinella Consortium Project).
The first cDNA microarrays have also been developed for B. azoricus and P. grasslei
and the aim is to use these as models in order to study the response of these organisms to temperature challenges, heavy metal effects and symbiosis. A recent study
has already demonstrated that deep-sea vent mussels can endure a global depression
in gene expression associated with short-term exposures (30–120 min) to temperatures higher than 20 ◦ C, suggesting that these animals are more likely adapted to
cold temperatures (Boutet et al. 2008).
3.4.4.2 Polar Environments
Living in the cold obviously has resulted in specialist genetic adaptations, of which
there are some classic single gene investigations:
• Plasma antifreeze: this was first discovered in Antarctic fish (DeVries 1970), but
now recognised as a standard adaptation to the cold marine environment (DeVries
1982).
• Specific protein modifications resulting in increases in molecule flexibility, essential for efficient functioning in the cold (Fields and Somero 1998, Detrich et al.
1989, 1992, Fields et al. 2002,Römisch et al. 2003).
• Deletion of haemoglobin genes and the ability to produce functional erythrocytes
in the Channichthyidae (icefish) (Moylan and Sidell 2000, di Prisco et al. 2002).
• Lack of the classical heat shock response (upregulation of the inducible form of
HSP70) in a number of fish and invertebrate species (Hofmann et al. 2000, Clark
et al. 2008a, c).
This latter “adaptation” has been recently investigated via a pilot microarray analysis hybridizing RNA from the Antarctic fish Trematomus bernacchii onto an array
produced for the eurythermal goby fish Gillichthys mirabilis (Buckley and Somero
2009). In this study they showed that the Antarctic fish, although not displaying
the classical heat shock response, did indeed show enhanced expression of many
genes associated with central aspects of the evolutionary conserved cellular stress
response. Whilst this experiment used a heterologous array approach, organismspecific arrays are now becoming available for some polar terrestrial insects
(cf. Purac et al. 2008) and it is expected that this will soon also be the case with
polar marine species.