Detection of infinitesimal gene
(Model experiment to detect gene existing in a extremely small amount in a sample)

In the genomic DNA derived from 10 of human blood, each of single copy genes

exists around at 1x 10 copies. However, the presence of provirus genes (e.g. HIV) is

very rare (1x 10 to 10) in the same genome. As a test experiment to detect these rare

genes, genes from mouse leucocyte mixed with those of human leucocyte (mixed ratio

mouse : human = 1:100 or 1:1,000) were successfully detected by using of the specific

primers for mouse gene.

Sample: 10
Mouse blood diluted with human blood to have the leukocyte ratio of human to mouse as;

            mouse : human =  1:100
             1:1,000

Primer:
1st exon in mouse K-ras

Amplified size:
205 bp (1st PCR)

108 bp (2nd PCR)

(Analyzed by a fluorescence imaging analyzer, after 2nd PCR.)