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ADVERSE IMPACTS OF TRANSGENIC CROPS/FOODS :A COMPILATION OF SCIENTIFIC REFERENCES WITH ABSTRACTS16. Duggan PA, Chambers PA, Heritage J and Forbes JM (2003) : Fate ofgenetically modified maize DNA in the oral cavity and rumen of sheep.British Journal of Nutrition 89: 159-66.The polymerase chain reaction (PCR) technique was used to investigate the fateof a transgene in the rumen of sheep fed silage and maize grains from an insectresistantmaize line. A 1914-bp DNA fragment containing the entire coding regionof the synthetic cryIA(b) gene was still amplifiable from rumen fluid sampled 5 hafter feeding maize grains. The same target sequence, however, could not beamplified from rumen fluid sampled from sheep fed silage prepared from thegenetically modified maize line. PCR amplification of a shorter (211-bp), yet stillhighly specific, target sequence was possible with rumen fluid sampled up to 3and 24 h after feeding silage and maize grains, respectively. These findingsindicate that intact transgenes from silage are unlikely to survive significantly inthe rumen since a DNA sequence 211-bp long is very unlikely to transmit geneticinformation. By contrast, DNA in maize grains persists for a significant time andmay, therefore, provide a source of transforming DNA in the rumen. In addition,we have examined the biological activity of plasmid DNA that had previously beenexposed to the ovine oral cavity. Plasmid extracted from saliva sampled afterincubation for 8 min was still capable of transforming competent Escherichia colito kanamycin resistance, implying that DNA released from the diet within themouth may retain sufficient biological activity for the transformation of competentoral bacteria.http://www.ncbi.nlm.nih.gov/pubmed/1257590017. Koonin EV (2003) : Horizontal gene transfer: the path to maturity. MolecularMicrobiology 50 (3) : 725-27.The realization that horizontal (lateral) gene transfer (HGT) might have had amajor impact on biological evolution is perhaps the most fundamental change inour perception of general aspects of biology brought about by massive genomesequencing (Gogarten et al., 2002; Doolittle et al., 2003). As Lawrence andHendrickson (2003) rightly point out in the MicroReview appearing in this issue,HGT might also be the most controversial topic in genomics. The main thesis oftheir review is that the study of HGT is still ‘in its adolescence’. They discuss fourmajor questions that, in their reckoning, should be addressed for HGT to graduateto adulthood:(i)(ii)(iii)(iv)How does HGT impact the evolutionary history of different genes?How does the role of HGT differ among different lineages?How does one reach robust conclusions on the presence or absence ofHGT?How does one integrate HGT into the continuum of genetic exchange toarrive at meaningful microbiological concepts?(186)