Fig. 2. Expression of D. rerio globins at different oxygen levels. mRNA quantities were determined by quantitative real-time PCR. The white columns represent mRNA levels from zebrafish kept for 48 h at normoxia (P_O2=18.4 kPa), grey columns are mRNA levels from zebrafish kept for 48 h at P_O2=8.6 kPa, black columns are mRNA levels from zebrafish kept for 48 h at P_O2=4.1 kPa. Values are means ± s.d. The significance of the data was estimated with a Student's t-test, with N=3 or 4 individuals for each data point. ^***P<0.001; ^**P<0.01. ARP, acidic ribosomal protein; Cygb, cytoglobin; GbX, globin X; Hb, hemoglobin; LDHA, lactate dehydrogenase A; Mb, myoglobin; Ngb, neuroglobin; PGK1, phosphoglycerate kinase 1.