1. This is a reciprocal F2 intercross between mouse strain PERA/EiJ and DBA/2J. The data set had been used in 2 publications for different phenotypes analysis. The cross file posted on website is merged from 2 separated files for these papers (Wittenburg 2005 and Wittenburg 2006). Please check the description file for the details of the references. The map of the data set has been updated with Build37 Cox genetic map (B37) and the new file is saved as "Wittenburg2005_PERAxDBA_B37_Data.csv". This file is ready to be read into Rqtl; 2. Generate a description file of the project, it includes the general information, definitions of the phenotypes, description of the genotypes and information of the missing markers; 3. For the genotypes of this cross: (cM=centimorgan, bp=basepair) (1) Changed the symbol of PERA allele from "0" to "A", DBA allele from "2" to "D", heterozygous alleles from "1" to "H", missing genotypes from "=" (original data) to "-" (standard format in data sets of QTL archive) and saved the changes in B37 data file; (2) Marker "D4Mit297" and "D7Mit248" missed bp position in both Cox map and MGI. Primer sequences found in MGI, but their locations didn't match the result from primer-BLAST in NCBI. We could not identify the B37 bp position of this marker currently (this type of markers is highlighted with rose color in description file); (3) Marker "D4Mit26" missed bp position in both Cox map and MGI. Primer sequences found in MGI, and their locations identified using primer-BLAST in NCBI followed by UCSC In-Silico PCR (this type of markers is highlighted with lime color in description file); (4) The bp position of marker "D13Mit256" was missing in both Cox map and MGI. No primer sequences were available for them from MGI. We could not identify the B37 bp positions for these markers currently (this type of markers is highlighted with pale blue color in description file); (5) Five markers missed bp positions in Cox genetic map, assign the positions from current MGI database. This type of markers are highlighted with gold color and please see description file for details; (6) Potential genotype errors have been detected by Rqtl program after data input -- 1 DD genotypes was found on females from (PxD)x(PxD) cross on the X chromosome; 4. For the phenotypes of the cross: (1) Changed the symbol of female mouse in "sex" trait from "F" to "0", male mouse from "M" to "1", saved the changes in B37 data file; (2) Add the trait "pgm" (paternal grandma) in B37 data file to indicate the cross direction (the original data didn't have this information); (3) This is a reciprocal intercross but the data file doesn't have the information of paternal grandma (pgm, which indicates the direction of cross), Rqtl generates a column named "pgm" automatically after the data input; (4) Trait "gallstone_presence" and "gallstone_present_absent" were merged from different data files. Although both of them indicated gallstones presence (score 0=absent, 1=present), we detected 19 different scores between them among the total 324 mice. So they were listed as separated phenotypes in B37 data file; 5. Except the "csv" file mentioned above, I also saved the description file, original data, data with B37 map, data process and list of missing markers together as a big excel file ("Data_Description_PERAxDBA_Wittenburg2005.xlsx") (1st curating work is finished on 2009, files are updated on 3/10/2011). 6. Information were updated on 5/30/2012: Change the name of the map (from "Shifman" to "Cox" map) in description and readme file, add a map reference in description file.