Worm Breeder's Gazette 13(4): 32 (October 1, 1994)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Strain Names for non-C. elegans Species.

Scott W. Emmons¹, Armand Leroi¹, David Fitch²

  In the past, non-C. elegans species have been maintained without any strain
designation, or sometimes with a two-letter postscript to indicate the site of collection.
As the study of evolution of nematodes begins, and more and more laboratories work
with increasing numbers of new species, this system is becoming burdensome. For
example, there is no way to indicate multiple isolations at a single site. Worms
originating from non-C. elegans laboratories tend to have no strain designation at all.
There is a tendency not to report a strain name when a non-C. elegans species is
mailed. Hence, independent isolates of species are being treated as equivalent, the
information about their independent origins being lost. When worms are frozen in
various laboratories, laboratory strain names, necessary for databases, are being
assigned, with the result that equivalent populations of worms can acquire several
different laboratory strain names.
  In view of this growing problem, we have developed the following
recommendation for the uniform assignment of strain names to non-C. elegans
species. We have reviewed these suggestions with Scott Baird, Lynn Carta, Bob
Herman, Jonathan Hodgkin, and Patrick Phillips, and they are in agreement. We
therefore suggest that the following practices be adopted:
  l. The old strain naming system, in which letters were placed after the species
name to indicate the site of collection, is dropped.
  2. Every population of worms has a single strain name in standard C. elegans
format, assigned by a laboratory with a two-letter designation registered with the
Caenorhabditis Genetics Center. The strain name is reported along with the species
name, in the following format: Rhabditis any species (EM0000).
  3. The strain name is assigned by the collecting laboratory. The collecting
laboratory is the first laboratory with a registered strain designation that receives the
population of worms. The worms might be collected from the wild, or they might be
received from a laboratory without a registered strain designation. The strain name
does not change as the worms are sent from laboratory to laboratory.
  4. The collecting laboratory is responsible for maintaining information
regarding the origin of the strain. Each population founded from a separate wild
isolation receives a new strain name (experience with C. elegans wild isolates
indicates these can differ significantly, eg with respect to transposon distribution). For
a hermaphroditic species, the "founding population" can be a single worm. However,
for male-female species, it is at least two worms, and could be many more, as there
may be a problem with inbreeding depression if the founding population is too small.
Therefore a strain designation does not imply uniform genetic homozygosity.