• E. S. Sachs


The normal human chromosome number is 46, 22 pairs of autosomes and two X chromosomes or an X and a Y chromosome. The G group contains the two smallest pairs of chromosomes, numbered 21 and 22. The occurrence of an extra chromosome in this group is called trisomy G and this phenomenon is present in all cells in patients with Down’s syndrome.

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© Springer Science+Business Media Dordrecht 1971

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  • E. S. Sachs

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