Defective megakaryocyte ploidy and circulating platelets in Plk1(Δ/Δ) mice. (A) Analysis of DNA content in gated CD41⁺ cells from the bone marrow of 8-week-old Plk1(Δ/Δ) or control mice. The plot is representative of 3 different animals analyzed per genotype. (B) DNA content in CD41⁺ cells from the bone marrow of mice with the indicated genotypes. Data are mean ± SD (n = 4 mice per genotype). *P < 0.05; **P < .01; ***P < .001; Student t test. (C) Number of circulating platelets in Plk1(Δ/Δ) or control mice. As a comparison, the average count is ∼100 × 10⁹ platelets/L in Cdc20-deficient mice.¹²  ***P < .001; Student t test.