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3. LeJeune, J., Gautier, M. & Turpin, R. Study of somatic chromosomes from 9 mongoloid children [French]. C. R. Hebd. Seances. Acad. Sci. 248, 1721–1722 (1959). This study is the first description of the chromosomal abnormality in DS.
4. Davisson, M. T., Schmidt, C. & Akeson, E. C. Segmental trisomy of murine chromosome 16: a new model system for studying Down syndrome. Prog. Clin. Biol. Res. 360, 263–280 (1990).
5. Hattori, M. et al. The DNA sequence of human chromosome 21. Nature 405, 311–319 (2000). A landmark paper on the sequencing of the long arm of HSA21.