This track shows Rat quantitative trait loci (QTLs) from the
Rat Genome Database (RGD)
that have been coarsely mapped by UCSC to the Human genome using
stringently filtered cross-species alignments.
A quantitative trait locus (QTL) is a polymorphic locus that contains alleles
which differentially affect the expression of a continuously distributed
phenotypic trait. Usually a QTL is a marker described by statistical
association to quantitative variation in the particular phenotypic trait that
is thought to be controlled by the cumulative action of alleles at multiple
For a comprehensive review of QTL mapping techniques in the rat, see Rapp, 2000.
To map the Rat QTLs to Human, UCSC's chained and netted blastz
alignments of Rat to Human were filtered to retain only those with
high chain scores (>=500,000). This removed many valid-but-short
alignments and in general retained only very long chains (>10,000,
usually >100,000 bp), so that only large regions could be mapped. This
choice was made because QTLs in general are extremely large and
approximate regions. After the alignment filtering, UCSC's liftOver
program was used to map Rat regions to Human via the filtered
To get a sense of how many genomic rearrangments between Rat and
Human are in the region of a particular Rat QTL, you may want to
view the Human Nets track in the Rat Nov. 2004 (Baylor 3.4/rn4) genome browser.
In the position/search box, enter the name of the Rat QTL of interest.
Thanks to the RGD for
providing the Rat QTLs. RGD is funded by grant HL64541 entitled "Rat
Genome Database", awarded to Dr. Howard J Jacob, Medical College of
Wisconsin, from the National Heart Lung and Blood Institute
(NHLBI) of the National
Institutes of Health (NIH).
Genetic analysis of inherited hypertension in the rat.
Physiol Rev. 2000 Jan;80(1):135-72.