为从少量标本中获得含较多大片段的、高质量的老年性白内障消减cDNA文库 ,利用磁珠分离、生物素标记的改良消减杂交法获得差异cDNA ,利用选择性PCR法扩增其中大片段差异cDNA ,从而成功构建老年性白内障消减cDNA文库 .在文库中随机挑取的 2 2个克隆中 ,10 0 0bp以上的片段有 7个 ,占 31 8% ,75 0bp以上有 15个 ,占 6 8 2 % .所得cDNA片段较大 ,可以满足下一步研究需要 .改良消减杂交法结合选择性PCR法可以从少量标本中快速有效地获得大片段高质量的消减cDNA文库 In order to obtain high-quality senile cataract subtracted cDNA library containing more large fragments from a small amount of samples, differential cDNAs were obtained by magnetic bead separation and biotin-labeled modified subtractive hybridization, and large fragment differences were amplified by selective PCR cDNA to successfully construct the senile cataract subtractive cDNA library.In the randomly selected 2 2 clones in the library, there were 7 fragments of more than 10 0bp, accounting for 31.8%, 15 of 75 bp or more, accounting for 68 2% .The obtained cDNA fragment is larger, which can meet the needs of the next research.Modified subtractive hybridization combined with selective PCR method can quickly and efficiently obtain a large fragment of subtracted cDNA library