Floxed mutation causes α-thalassemia. (A) Dissected E14.5 embryos. HS-26 genotypes are indicated at the top. (B) Blood smears from adult mice, stained with Wright-Giemsa (original magnification, × 100). Note the target cells, hypochromic cells, and prominent fragments in the blood from the floxed/floxed mice. A white blood cell (purple) is shown in each panel for size comparison.