Figure 3.

Population variation in human IGFBPs 1–3. A, diagram of the human IGFBP1 precursor, including the 25-residue SP and mature 234-amino acid (AA) IGFBP1. The overall population prevalence of variant alleles for each part of the molecule is listed below the map, and the location of the two most common variants is depicted in single-letter amino acid code. B, diagram of the human IGFBP2 precursor, including the 36-residue SP and mature 289-amino acid IGFBP2. The overall population prevalence of variant alleles for each part of the molecule is listed below the map, and the location of the most common amino acid variant is depicted in single-letter code. C, diagram of the human IGFBP3 precursor, including the 27-residue SP and mature 264-amino acid IGFBP3. The overall population prevalence of variant alleles for each part of the molecule is listed below the map, and the location of the four most common individual variants is depicted in single-letter amino acid code. The scale bar represents 20 amino acids for A–C. Protein segments for all three IGFBPs include NH₂-terminal, linker, and COOH-terminal domains.