Genetic Advancement in Tomatoes through ‘antisense’ Technology
Through the use of ‘antisense’ technology the tomato plant has been genetically advanced allowing it to stay firm for longer. The enzyme that allows normal tomatoes to become soft is no longer produced through this new technology. The ‘antisense’ technique works by switching off specific genes responsible for the production of particular enzymes or other proteins. It is through this new artificial ‘off switch’ that the research in fields as different as cancer therapy and plant breeding are being transformed.
‘Antisense’ technology is a process that works by interfering with the cells normal production. Within the cell the genes carry information, used to make particular proteins, as a code. This code is embodied in the sequence of four chemical bases in the two DNA strands that make up the double helix. These strands are bound together through the use of “base pairing” having complementary bases to one another. One of these strands is called the sense strand, this strand carries the information in a form that the cells are able to use to create proteins, and the other is called the antisense strand. A cell will normally decode the sense strand and copy its information onto single strands of RNA. The ‘messenger’ mRNA then carries this information to the ribosomes, the instructions carried within the mRNA are then use to find the correct amino acids to create proteins. It is with this process that genetic engineers have discovered how to interfere with cells.
Interfering with this process within the cell prevents them producing proteins from the specific genes that allow the tomato to become soft. The technique tricks the cells into using the antisense strand, instead of the sense strand, as the template for the messenger RNA. This is done by the introduction of an artificial gene that is “back to front” into the cell’s DNA. This is oriented in a way that the mRNA uses the antisense strand as the template instead of the sense strand. The mRNA that is produced from these antisense strands of DNA is complementary to the normal mRNA originally produced from that gene. These mRNAs are then ‘base paired’ to create a mini double helices of RNA. The ribosomes are unable to decode these mRNA when bound this way, and so no protein is made from this gene. The entire genes participation in the production of proteins is eliminated, as the mRNA’s binding to the antisense sequence is even more likely to be broken by enzymes. It is through this interference that the protein in tomatoes that allows them to become soft is no longer produced. Tomatoes with the ability to stay firm for longer are one of the first commercial applications of antisense technology.
Overall it is through ‘antisense’ technology that the tomato plant has been genetically advanced. It is through ‘tricking’ the cell that we are now able to ‘switch off’ the gene responsible for the tomato becoming soft. This technology is not only improving the product of tomato and their shelf life, but also revolutionising many areas of research.