FIGURE 8.1Chromosomes, DNA, and GenesEvery cell in your body, except red blood cells and sex cells (sperm or egg), contains a full set of 23 chromosome pairs like those shown in the photo below. These 23 chromosome pairs contain the full blueprint for you as a complete, unique person. The primary component of each chromosome is a single, tightly wound molecule of DNA. Within that DNA are around 21,000 genes, each determining specific traits such as hair texture.

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