1126 (CBA/CaH x QSi5)F2 animals. Parental strain QSi5 is derived from an outbred Quackenbush-Swiss line and displays higher platelet counts compared to CBA/CaH. 101 polymorphic markers at an average spacing of 15 cM were used in the genome scan.
Linkage to platelet count mapped to 94 cM on mouse Chromosome 1 near D1Mit540 (LOD=6.8). This locus is named Pltct1 (platelet count 1) and accounts for 5.6% of the genetic variance. QSi5-derived alleles confer decreased platelet count. Potential candidate genesfor Pltct1 are Astn1, Mgst3, Lbr (97.3 cM), 1810030J14Rik, and 4930403O06Rik. All potential candidate genes show differential expression between parental strains QSi5 and CBA/CaH.
Linkage to platelet count mapped to 45 cM on mouse Chromosome 11 near D11Mit325 (LOD=11.2). This locus is named Pltct2 and accounts for 9.2% of the genetic variance. QSi5-derived alleles confer increased platelet counts. Potential candidate genes for Pltct2 are Epx (49 cM), D11Ertd18e (45 cM), 1110033F04Rik, Krt1-2 (58.3 cM), Abca8b (69 cM), Birc5, Dcxr, Thoc4, and Olfr1. All potential candidate genes show differential expression between parental strains QSi5 and CBA/CaH. Pltct2 maps near a previously identified QTL for stem cell proliferation rate named Scpro2 (44 cM). The LOD score was greater than 4.3 for markers spanning most of the length of chromosome 11 indicating there may be more than 1 QTL present. A second QTL may be located around 8 cM (LOD=2).
Suggestive loci mapped to 24 cM on mouse Chromosomes 7 (LOD=3.6), 53 cM on mouse Chromosome 13 (LOD=3.4), and 20 cM on mouse Chromosome 17 (LOD=3.5).