5Hasson A.Satellitse associa tion in human metaphase.A comparative st udy of normal indviduals,patients with D owns syndrome and their parents[J].Hered itas,1979,90:59
6Richard CJ.Origin of nondisjunct ion in trisomy 21 syndrome;All studies c ompiled parental age analysis,and intern ational comparisions[J].Am J Med Genet,1 983,16:111
7Griffin DK.The incidence,origin,and et iology of aneuploidy[J].Intern Rev Cytol ,1996,167(1):263~296
8Zaragoza MV,Jacobs PA.Nondisjunction o f human acrocentric chromosomes:studies of 432 trisiomic fetuses and liveborns[J ].Hum Genet,1994,94(4):411~417
9Read SG.The distribution of Downs Synd rome[J].J Ment Defic Res1982,26(4):215
9Hasson A. Satellite association in humam metaphase. A comparative study of normalindviduals, patients with Down's syndrome and their parents. Hereditas, 1979, 90: 59