Fig. 3b shows that even low-level serum FGF2 decreased RBC count by 10–15% (P<0.05), while further increase in FGF2 led to an additional drop in the RBC count. In the high SFFV-FGF2 group, the RBC counts were decreased by ∼40% relative to control (P<0.001), leading to severe anemia. The observed anemia in animals with high serum FGF2 levels may have contributed to the retarded body weight gain and sickness in some animals. In the β-globin-FGF2 animals, the RBC counts were also decreased to the same level as in the low SFFV-FGF2 animals (Fig. 3b). Here, FGF2 is linked to anemia (phenotype).