Population differences in nerve resistance to paralytic shellfish toxins in softshell clam, Mya arenaria, associated with sodium channel mutations

Rapid gain and loss of evolutionary resistance to the harmful dinoflagellate Cochlodinium polykrikoides in the copepod Acartia tonsa

“…Thus, rapid gain and loss of resistance to C. polykrikoides may simply reflect switching between resistant and nonresistant genotypes in copepod populations. An alternative mechanism is that adaptive phenotypic plasticity (Ghalambor et al 2007) may contribute to the evolution of resistance to harmful algae. The freshwater grazer Daphnia galeata evolves resistance to cyanobacteria through reduced phenotypic plasticity (Hairston et al 2001).…”

“…Evolution occurring on ecological timescales affects population persistence, drives speciation or extinction ), alters community structure, and shapes ecosystem function (Post and Palkovacs 2009). Ecological variables, such as spatial habitat heterogeneity, dispersal (Grant et al 2007), and phenotypic plasticity (Ghalambor et al 2007), influence the potential for evolution. Some representative of rapid evolution, occurring over tens of generations or fewer, have been documented when a species is introduced into a new habit or when an environment is changed, especially by human activities (Levinton et al 2003;Carroll et al 2007).…”

“…The rapid adaptation in the Daphnia population was due to the evolution of reduced phenotypic plasticity, displaying a reduced degree of sensitivity to cyanobacteria (Hairston et al 2001). Both copepods (Colin andDam 2002, 2004) and clams (Bricelj et al 2005;Connell et al 2007) exposed to annual Alexandrium blooms have been shown to be more resistant to paralytic shellfish poisoning (PSP) than their conspecifics in nonbloom areas. This enhanced resistance in clams is caused by a natural mutation of a single amino acid residue, which greatly reduces the binding affinity of PSP toxins to Na + channels (Bricelj et al 2005).…”

Withdrawn: “A health status survey of clams, Mya arenaria and Ensis siliqua, in the Irish Sea”

“…This clam is currently fished on North American shores (Beal, 2002;Connell et al, 2007), and is considered a species of interest for future commercial exploitation in the Irish Sea. Ensis siliqua, the razor clam, is a native species in Europe, and is distributed along the European Atlantic coast from the Norwegian Sea south to the Mediterranean and along the Atlantic coast of Morocco (DaCosta et al, 2010).…”

Metapopulation dynamics of the softshell clam, Mya arenaria

“…Given that local adaptation has been noted in the softshell clam for toxin resistance (Connell et al, 2007), there may very well be important regional genetic differences among clam stocks in non-neutral genes. As such, seeding from local stocks should be preferred.…”