Dissecting quantitative trait loci into opposite blood pressure effects on Dahl rat chromosome 8 by congenic strains.
OBJECTIVE
Our previous linkage analyses showed that there was likely a quantitative trait locus (QTL) for blood pressure (BP) on chromosome 8 (Chr 8) in the strain comparison between the Dahl salt-sensitive (S) and the Lewis (LEW) rats. The current work is to delineate the chromosome interval harboring this QTL by using congenic strains with different chromosome substitutions.


METHODS
Two congenic strains were produced by replacing different segments of the S rats with the homologous segments of the LEW rats. A genome-wide marker screening was utilized to accelerate this process. The two strains generated are designated as C8S.L1 and C8S.L2, respectively. BPs of the rats were measured by telemetry.


RESULTS
C8S.L1 showed a BP lower than that of S rats. In contrast, C8S.L2 did not have chromosome overlaps with C8S.L1, but unexpectedly, exhibited a BP-raising effect, higher than that of S rats.


CONCLUSIONS
There are at least two QTLs present in a section of Chr 8 that possess opposite BP effects. The current congenic work reveals not only the presence of QTLs, but the complexity of QTLs on BP. The novel congenic strain with hypertension more severe than S provides a new model for studies in elucidating physiological mechanisms controlling BP.
Ariyarajah
Anita
A
Research Centre-CHUM, Hôtel Dieu, 3840 rue St Urbain, Montréal, Québec, H2W 1T8, Canada.
Palijan
Ana
A
Dutil
Julie
J
Prithiviraj
Kalyani
K
Deng
Yishu
Y
Deng
Alan Y
AY
D000818:Animals; D020296:Animals, Congenic; D001794:Blood Pressure / Q000235:genetics*; D002874:Chromosome Mapping; D033481:Chromosomes, Mammalian; D005819:Genetic Markers; D016678:Genome; D006973:Hypertension / Q000235:genetics*; D040641:Quantitative Trait Loci; D051381:Rats; D020303:Rats, Inbred Dahl / Q000235:genetics*; D011917:Rats, Inbred Lew
D005819:Genetic Markers