Gene Amplification Permits Minimally Invasive Analysis of Fish Mitochondrial DNA

Abstract Fish DNA was extracted from epithelial tissue covering a few scales and used as template for the polymerase chain reaction (PCR). Amplified segments of the mitochondrial DNA gene for 12S ribosomal RNA were subjected to restriction enzyme analysis. Restriction fragment length polymorphisms (RFLPs) are described for several fish species. Direct sequencing of amplified segments from largemouth bass Micropterus salmoides and channel catfish Ictalurus punctatus permitted interspecific comparisons and the development of detailed microrestriction maps that reveal diagnostic allelic variations between the two species. The protocol outlined in this report is offered as an alternative to conventional DNA analysis, which usually requires the obligatory sacrifice offish. It may be particularly advantageous when genetic analysis of valuable brood stock or endangered species is necessary because it obviates the need for animal sacrifice.