An article in the ScienceDaily website http://www.sciencedaily.com/releases/2007/05/070514170827.htm reports that scientists from the University of Missouri-Columbia has been able to successfully find a way to genetically engineer mini chromosomes in maize and attach genes that can add better characteristics depending on the genes used. Through this newly discovered practice, scientists may be more able to create and develop plants that can have multiple desired traits as well as more likely to have plants that have these same traits transferable to the next generation.
As published in the National Academy of Sciences James A. Birchler, professor of biological sciences in the MU College of Arts and Science and a team of other scientists (Weichang Yu, Fangpu Han, Zhi Gao, and Juan M. Vega) further made studies on a previous MU discovery about the creation of mini-chromosomes in order to show that genes could be stacked on them.
A mini-chromosome is a very tiny version of a normal chromosome which is the threadlike linear strand of DNA and associated proteins that carry genes, function and certain hereditary information of an organism. The difference between the two is that a chromosome is made of both centromeres and telomeres with much intervening DNA included whereas a mini-chromosome contains only the centromeres and telomeres and with little else. What makes mini-chromosomes a more appealing means for gene transfer is that they have better ability to accept the addition of new genes in subsequent experiments.
Mini chromosomes can function just the same way as normal chromosomes. More so, they can also allow genes to be stacked upon them, a function that chromosomes lack. Current genetic modification practice makes use of chromosomes during gene transfer which prevents scientists to stack up multiple genes especially on separate chromosomes independent of the others. Furthermore, gene transfer using chromosomes give scientists little control over where the transferred genes may be located in the chromosomes.
By stacking the genes on mini chromosomes, the team of scientists in MU have provided a way to have these transferred genes to be stacked up on just one location, allowing scientists to create plants with multiple beneficial traits such as resistance to pests, certain viruses, droughts and other stresses. This new discovery can pave the way for other scientists to be able to add numerous genes on certain plants and manipulate them since they can all be found in just one place, the mini chromosome.
Further research and studies will help scientists find other ways to make use of mini chromosomes in biotechnology. Other foreseen applications for the use of mini chromosomes in genetic modification include the production of multiple foreign proteins and other metabolites that can be used for medical purposes. And because a part of the maize kernel has a protein rich composition, they can be used through genetically modifying mini chromosomes in order to grow animal proteins as well as human antibodies that can be used to treat a variety of diseases.