Slot blotting of genomic tail DNA.

Slot or dot blotting is a technique whereby nucleic acids can be applied to a solid matrix, unfractionated, using a vacuum manifold. Slot blotting is the quickest, easiest, and, apart from polymerase chain reaction, probably the most sensitive assay of transgenic animal genotype (1). However, it can only be applied to animals that bear a transgene that has hybridizable segments with little or no homology to the host genomic DNA-for example, a hybrid gene with a viral or procaryotic reporter element, or a gene from another species with sufficient sequence divergence to allow the transgene to be distinguished from the host gene. Genomic slot blotting should not be used for the initial identification of a transgenic founder animal. For this, Southern blotting is preferable as it can give more information about the number of integration sites and the presence of transgene rearrangements, deletions, and so forth. However, genomic slot blotting is useful for the rapid screening of subsequent generations of transgenics when detailed information about the structure of the transgene is not needed.