Define recombinant DNA as genetic material joined from two or more sources, then identify the recombinant construct in biotechnology contexts using Cambridge A Level Biology mark schemes.
The potato plant, Solanum tuberosum, is an important food crop. Crop yield is reduced if the leaves of the plant are eaten by the larvae (immature stages) of the Colorado beetle, Leptinotarsa decemlineata.
Crop scientists used recombinant DNA technology to create two genetically modified (GM) varieties of potato plant. These plants produce proteins that are poisonous to insects.
- GM potato variety A contains two new genes, S N and Bt.
- GM potato variety B contains two new genes, SN and OCII.
The new varieties were tested by having a constant number of Colorado beetle larvae introduced to the plants at time 0 hours. The number of larvae that were alive after 24,48 and 72 hours was recorded. The percentage of the larvae that had died in each time interval was calculated. This was repeated for potato plants that had not been genetically modified (non-GM).
Table 4.1 shows the percentage of Colorado beetle larvae that had died on the GM potato plant varieties and on non-GM potato plants.
Table 4.1
Suggest what is meant by recombinant DNA technology.