PTA whole transcriptome
All samples (heart, liver, spleen, lung and kidney) were obtained from a female 2.5-years-old Siberian tiger, which was died in accident in the Heilongjiang Siberian Tiger Park. Additionally, a fresh placenta tissue was collected from a female 2.5 years old Siberian tiger within one hour of normal vaginal delivery. Total RNA was extracted from each tissue using the Trizol reagent (Invitrogen, Carlsbad, USA). The total RNA which was pooled heart, liver, spleen, lung, kidney and placenta RNA was used to contribute the cDNA libraries of PTA pooled sample.