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   CYTOGENETIC MAP

   by:  Michael Ashburner
   ____________________________________________________________________

     This is a cytogenetic map of D. melanogaster sorted by
   determined or estimated genetic map position. Estimated map
   positions are based on cytological positions, and where the
   published genetic map position is at variance with the known
   cytological position, an estimated map position (enclosed in
   brackets) is substituted for the published genetic position.
   There is approximate but not complete concordance between the
   map positions in this table and those in the individual
   entries in the body of this work. Loci mapped only to a chro-
   mosome, chromosome arm, or to a very long region  (e.g.,
   between v and f on chromosome 1) are excluded from this table.
   The other fields in the table are cytogenetic map position,
   gene symbol, and map index. The gene symbols in the table have
   been reconciled with those used in the body of the text
   insofar as possible; loci indicated in the table that are not
   represented in the text are designated with the symbol "-".
     Map index has been introduced to indicate absolute physical
   order within well mapped regions, this order usually being
   determined by deletion mapping or molecular methods. The rea-
   son for doing this is that published map positions, either
   genetic or cytogenetic, are inadequate to indicate the abso-
   lute order in many, if not most cases.  So as to allow this
   order to be generated by a program, rather than by hand, genes
   within well mapped regions are given an index which indicates
   this order. The map index has three components: a numbered
   division (1-104; numbers 103 and 104 are for the long and
   short arms of the Y chromosome respectively); a lettered sub-
   division, in lower case so as to avoid confusion with cyto-
   genetic positions, and an index number. If, within a lettered
   subdivision, two independent fine scale maps cannot be related
   with respect to each other, then the lower case letter of the
   index may be repeated. Examples of map indices are 1a100,
   24e1000, 24ee100. If two loci have not been separated, then
   they will have identical index numbers. Physical relationships
   are indicated by the fact that within a series of map indices
   (that is within a division or subdivision) a locus with the
   numerically lower index is physically to the left of one with
   a higher index. The index number is enclosed with () if only
   relative order is known. Map indices are not permanent attri-
   butes of loci (at least, not until the map is "complete").
   They will change as these tables are updated. Note that the
   sorting of loci in this table may well give an incorrect
   impression of physical order.