  Excitability is an attribute of life, and is a driving force in the descent
of complexity. Cellular electrical activity as realized by membrane proteins
that act as either channels or transporters is the basis of excitability.
Electrical signaling is mediated by a wave of action potentials, which consist
of synchronous redistribution of ionic gradients down ion channels. Ion
channels select for the passage of a particular ion species. Potassium ion
channels are gated by a variety of stimuli, including membrane voltage. Sodium
and calcium channels are gated only by membrane voltage, suggesting the
conservative argument that voltage-gated potassium channels are the founding
members of the voltage-gated ion channel superfamily. The principal focus of
this work is the investigation of the complement of potassium ion channels in
our genome and its generalizabilty. An array of issues relevant to excitability
is addressed, and a range of engagement in questions regarding the unity of
life is proffered.
