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Genomic DNA blot hybridization is traditionally used to demonstrate that, via genetic transformation, foreign genes are integrated into host genomes. However, in large genome species, such as Allium cepa L., the use of genomic DNA blot hybridization is pushed towards its limits, because a considerable quantity of DNA is needed to obtain enough genome copies for a clear hybridization pattern. Furthermore, genomic DNA blot hybridization is a time-consuming method. Adaptor ligation PCR (AL-PCR) of genomic DNA flanking T-DNA borders does not have these drawbacks and seems to be an adequate alternative to genomic DNA blot hybridization. Using AL-PCR we proved that T-DNA was integrated into the A. cepa genome of three transgenic lines transformed with Agrobacterium tumefaciens EHA 105 (pCAMBIA 1301). The AL-PCR patterns obtained were specific and reproducible for a given transgenic line. The results showed that T-DNA integration took place and gave insight in the number of T-DNA copies present. Comparison of AL-PCR and previously obtained genomic DNA blot hybridization results pointed towards complex T-DNA integration patterns in some of the transgenic plants. After cloning and sequencing the AL-PCR products, the junctions between plant genomic DNA and the T-DNA insert could be analysed in great detail. For example it was shown that upon T-DNA integration a 66 bp genomic sequence was deleted, and no filler DNA was inserted. Primers located within the left and right flanking genomic DNA in transgenic shallot plants were used to recover the target site of T-DNA integration.

Human papillomavirus (HPV) infection in the cervix was studied by pathomorphology for the first time in China according to Meisels and Fortin's criteria. Cervical condyloma was found in 257 out of 357 (71.99%) cervical tissues. 141 were simple condyloma, 50 dysplasia with condyloma and 66 carcinoma with condyloma. A zone of continuous transformation was observed between the condyloma and dysplasia or carcinoma. 141 simple condylomas were initially diagnosed as chronic cervicitis in 94 (66.67%) and as dysplasia in 29 (20.57%). The pathomorphologic features of condyloma have not been fully recognized before. In carcinogenesis of the cervical carcinoma, the fact that condyloma associated becomes severer in extent but less in incidence, conforms well to Meisels' view that condyloma is the precursor of carcinoma in situ. It is suggested that HPV infection is closely related to cervical carcinoma.