FIGURE 3.2 Karyotype This color-enhanced micrograph, called a karyotype, shows the 23 pairs of chromosomes in a healthy human male. As you can see, in nearly all cases, the chromosomes of each homologous pair are roughly the same size. The notable exception is the sex chromosomes (middle of bottom row): the Y chromosome that determines maleness is much smaller than the X chromosome. A woman’s karyotype would contain two X chromosomes.
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