Fine mapping of a QTL for indicators of submaximal
exercise capacity in the HERITAGE Family Study
Treva Rice
Division of Biostatistics
Washington University in St Louis
Friday, October 19, 2007, 12:30–1:30 pm
GEMS classroom, 3rd Floor in
Shriner's Building
Coffee, tea, and cookies will be provided
Abstract
The HERITAGE Family Study was designed to investigate the genetic factors
underlying the cardiovascular responses to regular exercise for a variety of
physiological and metabolic traits. One of the results from this study
involves oxygen consumption at an exercise workload of 60% of maximal
capacity (VO260), which indexes aerobic fitness in terms of the ability of
the circulatory and respiratory systems to supply oxygen to skeletal muscles
during sustained physical activity. Regular exercise makes these systems more
efficient by (among other things) enlarging the heart muscle and enabling
more blood to be pumped with each stroke, thus increasing the amount of
oxygen that is inhaled and distributed to body tissues. To put this measure
into perspective, the Cooper test of aerobic capacity is a function of the
distance (in meters) covered in 12 minutes. Untrained adults average
38-45 ml/min/kg, while world class trained athletes exceed 80-90 ml/min/kg.
Genome-wide linkage analysis of nearly 600 microsatellite markers revealed
a lod score of over 3.00 in a relatively narrow region of chromosome 13
for the VO260 response to 20 weeks of endurance exercise training.
We recently followed up this signal with fine mapping of over 1800 SNPs
in an approximately 8 Mb region. Today's discussion covers some of
the preliminary results of our fine mapping studies in this region.