Artificial selection for intrinsic aerobic endurance running capacity in rats.
Artificial selection for intrinsic aerobic endurance running capacity was started using genetically heterogeneous N:NIH stock of rats as a founder population (n = 168). Selection for low and high capacity was based upon distance run to exhaustion on a motorized treadmill using a velocity-ramped running protocol. The starting velocity was 10 m/min and was increased by 1 m/min every 2 min (slope was constant at 15 degrees ). At each generation, within-family selection was practiced using 13 families for both the low and high lines. A rotational breeding paradigm maintained the coefficient of inbreeding at less than 1% per generation. On average the founder population ran to exhaustion in 355 +/- 11 m. Six generations of selection produced lines that differed in running capacity by 171%, with most of the change occurring in the high line. At generation 6 the low line ran 310 +/- 8 m and the high line 839 +/- 21 m at exhaustion. Selection for running capacity produced changes in body weight as a correlated trait. By generation 6, the low-line females were 20% heavier than the high-line females, and the low-line males were 16% heavier than the high-line males.
Koch
L G
LG
Functional Genomics Laboratory, Medical College of Ohio, Toledo, Ohio 43614-5804, USA. lkoch@mco.edu
Britton
S L
SL
D000818:Animals; D001835:Body Weight / Q000235:genetics; D001947:Breeding / Q000379:methods; D005260:Female; D018703:Founder Effect; D008297:Male; D009043:Motor Activity / Q000235:genetics*; D051381:Rats; D012420:Running; D012641:Selection, Genetic