Identification Of Unknown Whale Bones Based On Cyt B Gene Sequences

Cetacea is a kind of marine mammals with great economic value, thus, human hunt them for centuries. In addition, their habitats are destroyed and the environment deteriorates, so the population of cetacea declines rapidly, and some species become endangered. The change causes scientists' attention and they begin to do some researches such as investigation of cetacea's population, establishment of stranding network, bycatch and poisonous substances in cetacea. Since 1980s, molecular biology has developed quickly and molecular techniques for evolution and population genetics appeared. All the techniques have been used in cetacea research step by step.Genome DNA is extracted by proteinase K and phenol/chloroform. Some improvements are made: 1) Bone powder is dipped in sterilized water before being digested; 2) Concentration of proteinase K is increased to 0.3mg/ml; 3) Two-times extraction with phenol/ chloroform/ isoamyl alcohol (25:24:1) is followed by two-times extraction with chloroform/ isoamyl alcohol (24:1). The results of this experiment are:1) Genome DNA is extracted from samples V1, V2, V3, V5, R, Z1 respectively and the result reveals genomic DNA is slightly degraded;2) Amplification products of samples V1, V2, V5, Z1 are got by PCR and agarose gel electrophoresis shows that the molecular weight of the amplification products are about 550bp;3) The amplification products are sent out for sequences. The sequences of samples V2, V5, Z1 are the same, so they are the same haplotype;4) The blasting result in GenBank shows that sample V1 has maximal similarity with Balaenoptera omurai, it is 99%; samples V2, V5, Z1 have maximal similarity with Balaenoptera acutorostrata, it is 98%. It indicates that sample V1 is Balaenoptera omurai and samples V2, V5, Z1 are Balaenoptera acutorostrata;5) The phylogenetic trees based on UPGMA and NJ are consistent with the blasting results;6) Analysis of software MEGA shows that the Cyt b gene sequence of the sample V1 has 1-2 nucleotides which are different from the homologous sequence of B. omurai (accession AB201257, AB201256), so the sequence is a new haplotype. Samples V2, V5, Z1 have the same Cyt b gene sequence and the sequence has 7 nucleotides which are different from the homologous sequence of B. acutorostrata (accession AJ554054), so it is a new haplotype too.