February 15-18, 2009 Washington State Convention Center Seattle ...

GENETIC ANALYSIS OF MICROSATELLITE MARKERS LINKED TO SPAWNING TIME
QTLs IN BROODSTOCKS OF RAINBOW TROUT Oncorhynchus mykiss WITH TWICE-
ANNUALLY SPAWNING TIME
Nelson Colihueque*, Rosy Cárdenas, Lorena Ramírez, Francisco Estay and Cristian Araneda
Departamento de Ciencias Básicas
Universidad de Los Lagos
P.O. Box 933, Osorno, Chile
ncolih@ulagos.cl
Broodstocks with a double annual reproductive cycle (DARC) that determine twice-annually spawnings are present in the rainbow
trout. The genetic basis for this behavior is unknown. Nevertheless, it is presumed that it would be related to the spawning
time character (SPT), which is controlled by quantitative trait loci (QTLs). Several microsatellite markers linked to QTLs
for SPT have been described (Sakamoto et al., 1999; O´Malley et al., 2002). This information is useful in order to know the
existence of QTLs for SPT in different broodstock populations, through marker-character association studies. This study was
undertaken to determine the existence of association between microsatellite markers linked to QTLs for SPT with the DARC
trait, present in female broodstock of rainbow trout population, cultured in southern Chile.
A stock, carrier of the DARC trait (twice-spawner, Whyteville 02 strain), was studied together with another non-carrier stock of
this trait (once-spawner, Steelhead strain). Samples of specimens of these two populations were genotyped with six microsatellite
markers linked to QTLs for SPT, and four that were unlinked. Microsatellites were amplified by PCR and the genotypes
determined by polyacrylamide gel electrophoresis. The interpopulational allelic frequency heterogeneity was determined, as
well as the Choulakian and Mahdi (2000) marker-character association index.
Three microsatellite loci linked to QTLs for SPT (One3ASC, One19ASC and One112ADFG) presented allelic heterogeneity
and a highly significant marker-character association with the DARC character (Table 1). On the other hand, none of the microsatellite
loci that were not linked to QTLs for SPT presented this pattern. The results indicate that the DARC trait in rainbow
trout would be based on the existence of QTLs for SPT. The present study contributes to knowledge of the genetic basis of
the DARC trait in this species and to its potential use in salmon farming. This study was financed by the grant FONDECYT
1060623.