Ferguson-Smith M A, Aitken D A
Birth Defects Orig Artic Ser. 1982;18(2):24-42.
Unbalanced chromosome aberrations detected by routine chromosome diagnostic services can be used for gene mapping by gene dosage. This procedure, once discredited by early observations in Down's syndrome, has now provided some of the most precise intrachromosomal gene localizations known and these are reviewed. Cytogeneticists have an obligation to see that every opportunity is taken to obtain mapping information from suitable cases. Interpretation of cytogenetic findings may be improved by application of appropriate gene dosage studies, and examples are described in which a diagnosis was made possible by such studies. Cytogeneticists may also contribute to human gene mapping by application of the technique of in situ molecular hybridization. The localization of the immunoglobulin kappa light chain genes (IGKV) to the short arm of chromosome 2 reported at this workshop provides the first example of the localization of an unassigned, unique DNA gene sequence by this method. Combined with the use of chromosomal translocations, resolution of assignments to chromosomal sub-bands is possible, and, as suitable DNA clones become available, the technique should have wide applicability in human gene mapping.
常规染色体诊断服务检测到的染色体不平衡畸变可用于通过基因剂量进行基因定位。这一程序曾因早期对唐氏综合征的观察而受到质疑，但现在已提供了一些已知的最精确的染色体内基因定位信息，本文对此进行了综述。细胞遗传学家有责任确保抓住每一个机会，从合适的病例中获取定位信息。应用适当的基因剂量研究可能会改善细胞遗传学结果的解释，并描述了通过此类研究得以确诊的实例。细胞遗传学家还可通过应用原位分子杂交技术为人类基因定位做出贡献。本次研讨会报告的免疫球蛋白κ轻链基因（IGKV）定位于2号染色体短臂，是通过该方法定位未分配的独特DNA基因序列的首个实例。结合染色体易位的使用，有可能将定位解析到染色体亚带，并且随着合适的DNA克隆可用，该技术在人类基因定位中应具有广泛的适用性。
