The article describes the development and application of conserved primers for amplifying and sequencing mitochondrial DNA (mtDNA) from a wide range of animal species using the polymerase chain reaction (PCR). The authors designed three pairs of primers that can amplify homologous segments of mtDNA from various animals, including mammals, birds, amphibians, fishes, and some invertebrates. These primers were effective even with unpurified mtDNA from nanogram samples of fresh specimens and microgram amounts of preserved tissues. The sequences obtained from bird and fish mtDNA show a strong bias toward transitions, similar to mammals, but with a higher frequency of thymine-to-cytosine transitions due to the light strand's deficiency in thymine. The amino acid replacements in the cytochrome b gene are faster in mammals and birds compared to fishes, aligning with the structural hypothesis for cytochrome b. The study highlights the utility of these primers for phylogenetic and population research, offering a fast and efficient method for mtDNA sequencing.The article describes the development and application of conserved primers for amplifying and sequencing mitochondrial DNA (mtDNA) from a wide range of animal species using the polymerase chain reaction (PCR). The authors designed three pairs of primers that can amplify homologous segments of mtDNA from various animals, including mammals, birds, amphibians, fishes, and some invertebrates. These primers were effective even with unpurified mtDNA from nanogram samples of fresh specimens and microgram amounts of preserved tissues. The sequences obtained from bird and fish mtDNA show a strong bias toward transitions, similar to mammals, but with a higher frequency of thymine-to-cytosine transitions due to the light strand's deficiency in thymine. The amino acid replacements in the cytochrome b gene are faster in mammals and birds compared to fishes, aligning with the structural hypothesis for cytochrome b. The study highlights the utility of these primers for phylogenetic and population research, offering a fast and efficient method for mtDNA sequencing.