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Karyotyping looks at the number, size, and structure of all your human chromosomes. It can pick up approximately 5% of all human mutations, but only if they involve millions of deleted, duplicated, or inverted letters. For example, just recently, they found a common inversion of 1.6 million letters. The letters are being completely inverted, and this is on the male-specific Y chromosome. It’s finding as many as one in five males in Eastern European ancestry. If you’ve got this inversion, such males are eight times more likely to suffer sperm-specific infertility problems; the male lacks this inversion. This is only a recent finding. Karyotyping can also pick up either complete chromosome duplication. For example, Kleinfelder Syndrome causes infertility in males due to an extra X chromosome being present. So normal males have got 1 X and a Y; with Kleinfelder, they’ve got 2 X chromosomes and a Y.
