From Dave Matthews, 4/10/95
 
 
               How to Create 2_Point_Data Records for GrainGenes
 
     A 2_Point_Data record is a GrainGenes object describing the genetic
 distance between two loci.  Usually the distance is not part of a complete
 map, but was measured individually because it was of special interest, e.g.
 because one or both of the loci are genes.
 
 EXAMPLE
 
 2_Point_Data : "Lr9/OPJ13"
 Locus_1 "Lr9"
 Locus_2 "OPJ13"
 Distance 0
 Female_parent "Arina (P11)"
 Male_parent "Oberkulmer"
 Number_of_individuals 156
 Reference "TAG-88-110"
 Contact "Keller, Beat"
 Data_source "Penner, Greg" 94.11.16
 
 Associated with any 2_Point_Data record would be additional information in
 regular Locus records like:
 
 Locus "Lr9"
 Type "Gene"
 Associated_gene "Lr9 (Triticum)"
 Chromosome "6B"
 Chromosome_arm "6BL"
 
 , as well as Germplasm records for the parents, the Reference record, and
 Colleague records.
 
 
 
 FIELDS AVAILABLE
 
 Note that some fields are alternative options; no record would contain
 values for all of these fields.
 
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 Field name             Sample Entry       Description or List of Choices
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 2_point_data           Lr9/OPJ13          Names of the two loci, gene first
 
 Locus_1                Lr9                Name of first locus
 
 Locus_2                OPJ13              Name of second locus
 
 Distance               0                  Distance between loci
 
 Error                  10                 Uncertainty in distance estimate
 
 Distance_units         "% recombination"  Units for distance value [Any text]
 
 Linkage                "Real close"       Textual qualitative evaluation, if
                                           no numeric value given in Distance
 
 QTL                    ---                If field "QTL" is present, one of 
                                           the Loci is a QTL.
 
 Female_parent          "Ace CItr13384"    ID of Germplasm record corresponding
                                           to female parent.  Include accession
                                           number if possible.
 
 Male_parent            "Baca CItr15891"   Male parent
 
 Parent                 "Baca CItr15891"   If cross was reciprocal or unknown
 
 Generation             "F2"               Kind of mapping population
 
 Number_of_individuals  156                Size of progeny population scored
 
 Method                 ?                  (Would this be a useful field?)
 
 Contact                "Keller, Beat"     Name of Colleague who did the work,
                                           and/or the Principal Investigator
 
 Reference              "TAG-88-110"       ID of literature Reference record
 
 Remark                 "Hot marker!"      [Any text]
 
 Data_source            "Penner, Greg" 94.11.16    Colleague and date submitted
 
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