Distinct QTLs are linked to cardiac left ventricular mass in a sex-specific manner in a normotensive inbred rat inter-cross.
Genetic mapping of the progeny of an F(2) inter-cross between WKY and WKHA rats had previously allowed us to detect male-specific linkage between locus Cm 24 and left ventricular mass index (LVMI). By further expanding that analysis, we detected additional loci that were all linked to LVMI in a sex-specific manner despite their autosomal location. In males, we detected one additional locus (Lvm 8) on Chromosome 5 (LOD=3.4), the two loci Lvm 13 (LOD=4.5) and Lvm 9 (LOD=2.8) on Chromosome 17, and locus Lvm 10 (LOD=4.2) on Chromosome 12. The locus Lvm 13 had the same boundaries as locus Cm 26 previously reported by others using a different cross. None of these loci showed linkage to LVM in females. In contrast, we identified in females the novel locus Lvm 11 on Chromosome 15 (LOD=2.8) and locus Lvm 12 (LOD=2.7) that had the same boundaries on Chromosome 3 as locus Cm 25 detected previously by others using a cross of other normotensive strains. In prepubertal males, there were no differences in the width of cardiomyocytes from WKY and WKHA rats, but cardiomyocytes from WKHA became progressively wider than that of WKY as sexual maturation progressed. Altogether, these results provide evidence that distinct genes may influence LVMI of rats in a sex-dependent manner, maybe by involving sex-specific interactions of sex steroids with particular genes involved in the determination of LVMI and/or cardiomyocyte width.
Llamas
Bastien
B
Experimental Cardiovascular Biology Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada, H2W 1R7.
Jiang
Zhibin
Z
Rainville
Marie-Line
ML
Picard
Sylvie
S
Deschepper
Christian F
CF
D000818:Animals; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D005260:Female; D023281:Genomics; D006352:Heart Ventricles / Q000033:anatomy & histology*; D008126:Lod Score; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D009929:Organ Size / Q000235:genetics; D040641:Quantitative Trait Loci; D051381:Rats; D011919:Rats, Inbred Strains; D012737:Sex Factors