Feasibility of the DNA methylation technique for age determination in the Antarctic minke whale
Mutsuo Goto, Toshihide Kitakado, Mioko Taguchi and Luis A. Pastene
International Whaling Commission
In this study, we investigated the feasibility of the DNA-methylation (DNA-M) technique to determine age in the Antarctic minke whale. A total of 100 Antarctic minke whale samples, for which earplug readings were considered excellent or good, were selected for the DNA-M feasibility study. Seven CpG sites in three genes (TET2, CDKN2A and GRIA2) were selected for this study because they showed significant correspondence between CpG methylation levels and age in a previous study on humpback whales. In addition, we investigated changes in the DNA-M rate among different positions of the whale’s body, some involving dorsal side (expose to sunlight) and others on the ventral side. DNA-M rate of the seven CpG sites were scored successfully and regressions of each CpG methylation against age determined by earplug were conducted. Coefficient of determination (R2) of all CpG sites were lower than that of the previous humpback whale study. The assay predicts age from skin samples with a standard deviation of 8.865 years. DNA-M rate fluctuated among 8-10 positions of the whale body. It is concluded that age determination of Antarctic minke whale based on the seven DNA-M sites (from three loci) used in this study is not feasible particularly for use in population dynamics models such as SCAA.