ARS | Publication request: USE OF DNA MARKERS TO IDENTIFY SELECTED STRAINS OF CHANNEL CATFISH

Submitted to: Catfish Culture Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: February 28, 1997
Publication Date: N/A

Technical Abstract: Identification of individual or related fish is necessary for efficient selective breeding and broodstock management, and for measuring traits such as individual spawning success, but the physical characteristics of channel catfish hinder identification. We have focused on the identification and utilization of DNA markers termed "microsatellites" that consist of tandemly repeated, short DNA sequences. To date, we have characterized 22 microsatellite markers in populations of wild and domesticated fish. The markers contain from 3 to 17 variants each in the wild population, and each fish contains one or two of these variants for each marker. For 14 of the markers, over 70% of the wild fish contained two variants, and this high level of variation was also seen in populations of domestic, farm-raised catfish and the foundation stock of the USDA 103 research strain. Identification of individuals using microsatellite markers has allowed unambiguous determination of spawn parentage from communal ponds, and data from several broodstock ponds has confirmed multiple spawning by male channel catfish in one breeding season. Microsatellite marker screening will be used to characterize and manage genetically improved lines of catfish released to commercial producers. Marker screening of genetically selected broodstock prior to the spawning season will allow breeders to choose which marker variants will exist in the offspring. Therefore, the markers can be used to track these fish as they are released to commercial producers and will allow researchers and producers to maintain the genetic integrity of the selected populations.