Determining Blue Whale ( Balaenoptera musculus ) Population Structure Using Introns Of Conserved Nuclear Genes


Although endangered, very little is known about the population structure of the blue whale (Balaenoptera musculus). The recovery plan for the species prepared by the National Marine Fisheries Service specifically recommends that both mitochondrial and nuclear DNA be analyzed to determine the stock structure. I plan to use introns of conserved nuclear genes to address this question. Genes which code for fundamental proteins arc highly conserved, however, they are interspersed with intron regions which are more mutable. Several researchers have designed primers for the polymerase chain reaction (PCR) that anneal to the conserved regions and are effective in amplifying the variable intron regions for many species across broad taxonomic groups. The exploration of introns in this project may significantly contribute to the conservation of other marine mammals by making more nuclear markers available for genetic research. Preliminary results indicate that the level of variation in introns of blue whales is relatively high and that the primers for PCR can be successfully applied to distant species within the Order Cetacea. We are in the first phase of this project which involves screening introns to find those with the most potentially informative variation. For this phase we are using biopsies of 8 individual blue whales taken from distant regional populations. The screening is being conducted using PCR and single-stranded conformational polymorphisms (SSCP). We have found that 7 out of 10 loci we screened in blue whales are polymorphic. The number of alleles at each locus ranged from 2-6. Using identical PCR primers and conditions we were able to amplify what appear to be the same loci in sperm whales ( Physeter macrocephalus ) and harbor porpoises.

Conway, C., R. Sears, and B. May. 1999. Determining Blue Whale ( Balaenoptera musculus ) Population Structure Using Introns Of Conserved Nuclear Genes. Presentation to the 13th biennial conference on the Biology of Marine Mammals, Maui , Hawaii , November 28 – December 3, 1999.