Expression of calmodulin genes in human heart. A, Chromosomal locations of the three human calmodulin genes indicated on ideograms representing G-banded chromosomes. B, Relative expression of mRNA for CALM1, CALM2, and CALM3 in normal human heart (left ventricle) normalized to expression of β-actin as determined by real-time quantitative RT-PCR using gene-specific Taqman probes. Human heart samples include fetal (n = 4), infant (n = 4), and adult (n = 8) developmental stages. Data plotted are mean ± SEM. Differences in expression among the three genes were significant (p<0.05; one-way ANOVA) in fetal, infant and adult hearts.