= Species, populations and strains
A <species> can encompass many <biological populations>. A <biological population> specifies a set of <organisms> in a place and time; a <biological strain> identifies a maintained variant or lineage, often in a laboratory. A <species> name, a local census and a <biological strain> designation therefore describe different things. Multiple independently maintained cultures can also share the same <biological strain> designation.
For example, a culture identified as <Escherichia coli> K-12 MG1655 specifies more than the <species> alone. Two flasks inoculated from that culture are separate experimental <biological populations>; the separate containers do not establish two <species> or two different <biological strains>. This is an original experimental bookkeeping example, not a claim that every <biological strain> name encodes a complete <genotype>.
Back to article page
