Early mapping studies including those conducted by Chao et al. [ 1] using RFLPs to map markers on chromosome group 7 confirmed strong conservation of gene order between chromosomes of each genome.
Therefore, we chose a simple approach to detect association decay with distance in order to select a region to perform a further fine-mapping study including a more dense screening over the selected region and sample replication for which multiple testing correction may be required.
Other genes that have appeared recently from various mouse mapping studies include the Duffy antigen receptor for chemokines (Darc) [ 55], endothelin-converting enzyme 1 (Ece1) [ 56] and secreted frizzled related-protein 4 (sFRP4) [ 57].
This bridge marker frequency is comparable to other recent consensus map studies, including [ 34] who used 10% of all markers as bridge markers to construct a consensus map for barley from 3 doubled haploid populations.
Out of 702 new SSRs, 121 SSR markers were successfully mapped in the present study, including 41 markers from genomic DNAs and 80 from the EST database.
A total of 11 candidate sex genes have been mapped prior to this study, including 3 different transcripts of wt1 [ 49], three sox9 loci [ 31] and 2 sox6 genes, Amh, DMRT1 and Nrob1 [ 31].
MH was the executive person in this study, including phenotyping, mapping procedure and statistical analyses, TM made the concept and wrote the manuscript.
The merged SNP dataset used in this study, including SNPs mapping onto A. thaliana cDNAs (TAIR7), is publicly available and downloadable via The GABI Primary Database (GabiPD; http://www.gabipd.org/) [ 57].
Although our analyses suggest that the multiple SNPs we found in association with serum retinol in each gene neighborhood were from common loci, there may be additional functional loci in each of these genes that remain to be found through further study, including fine mapping.
An updated WGRH3000 map was developed in this study, including 4690 new SNP loci and 1125 previously typed markers.
