SYSTEM FOR LASER/MECHANICAL DISSECTION OF CHROMOSOMES

越来越多的疾病与特定的染色体异常有关，如易位、倒位和缺失。单个染色体G-带的选择可以为染色体分析和这些异常的识别准备临床诊断探针。目前，所需的染色体条带是通过连接到液压机械手上的微吸管从玻片上刮下来的，同时使用配备100倍物镜的倒置显微镜来监测这一过程。针大致垂直于感兴趣的染色体，既将所需材料与染色体的其余部分区分开来，又将材料移除以进行后续处理。在一个正在开发的新系统中，使用紫外线(390 Nm)激光来非常精确地标定要获取的材料，并烧蚀紧邻周围的材料。然后，在计算机控制下，由专门开发的机构移动的微型吸管将所需的材料移除。人们希望，通过依靠激光来修剪掉不需要的物质，比起利用微吸管的剪切作用将样品从剩余物质中分离出来时，将会有更少的外来物质。此外，通过用物镜焦点位置和视频图像来感知针尖位置，以及使用计算机来确定机构的运动，将大大降低对操作员的手动灵活性要求，从而使该技术得到更广泛的应用。-染色体条带获取、细胞遗传学显带、DNA扩增、基因组定位

An increasing number of diseases are being associated with specific chromosomal abnormalities, such as translocations, invertions, and deletions. Selection of individual chromosome G-bands allows preparation of clinical diagnostic probes for chromosomal analysis and identification of these abnormalities. Presently, the desired chromosome band is removed by scraping it off a slide with a micropipette attached to a hydraulic manipulator while monitoring the process using an inverted microscope equipped with a 100X objective lens. The needle, oriented approximately perpendicularly to the chromosome of interest both demarcates the desired material from the rest of the chromosome, and removes the material for subsequent processing. In a new system under development, a UV (390nm) laser is used to very sharply demarcate the material to be acquired and ablate the immediate surrounding material. The desired material is then removed by a micropipette moved by a specially developed mechanism under computer control. It is hoped that by relying on the laser to trim away the undesired material, there will be less extraneous material than when the shearing action of the micropipette is used to separate out the sample from the remaining material. In addition, by sensing the needle tip position with the objective lens focus position and a video image, as well as employing a computer to determine the motions of a mechanism, the manual dexterity requirements on the operator will be greatly reduced, thus allowing the technique to be more widely used. - Chromosome band acquisition, cytogenetic banding, DNA amplification, genomic loci