过去廿年,人类细胞遗传学有了巨大的发展。至今,已作了二百万人的染色体组型分析。异常染色体组型的范围估计可能占所有人类合子的15％,流产儿的25％,在未经选择的新生儿中约占0.5％。在小鼠中,所有具有不平衡易位染色体组型的胚胎几乎经常是死的,与此相反,在人类许多这样的个体出生时是活的。性染色体非整倍体的研究,揭示了Y染色体在性决定中的作用,而且有助于发现女性体细胞中有一条失活的X染色体。大约在1970年首先发展的染色体显带技 Over the past twenty years, there has been a tremendous growth in human cytogenetics. To date, 2 million people have been analyzed for their genomes. The range of anomalous karyotypes may account for 15% of all human zygotes, 25% of aborted children, and about 0.5% of unselected neonates. In mice, all embryos with an unbalanced translocation genotype are almost always dead, whereas many human beings are alive at birth on the contrary. Studies of sex chromosome aneuploidy have revealed the role of the Y chromosome in sex determination and have contributed to the discovery of an inactivated X chromosome in female somatic cells. Chromosome banding developed first around 1970