6533b823fe1ef96bd127f604

RESEARCH PRODUCT

Mitochondrial DNA variability of striped dolphins (Stenella coeruleoalba) in the Spanish Mediterranean waters

subject

description

Frozen muscle samples from 44 striped dolphins stranded on the Spanish Mediterranean coasts from 1990 to 1993 have been studied by means of mitochondrial DNA (mtDNA) restriction site analysis. Thirty-five of these dolphins were affected by a die-off occurring during this time in the western Mediterranean Sea. The mtDNA from each dolphin was digested with 15 restriction endonucleases that recognized 61 different restriction sites. The specific location of these sites on the mitochondrial gene map allowed us to determine the distribution of variability along this molecule. From the restriction analysis, a total of 15 different composite patterns or haplotypes was obtained and their phylogenetic relationships established both by cladistic and phenetic methods. Estimates of sequence divergence among the 15 haplotypes ranged from 0.148% to 0.919%. Haplotype diversity (average heterozygosity) obtained was 0.789, a high value compared to other available data on cetaceans, especially considering that only a small area of the distribution of the species has been sampled. Neither population subdivision nor any evidence of correlation between haplotype frequencies and temporal or geographic distribution of dolphins has been detected.