Reasons to Believe

DNA Barcodes Used to Inventory Plant Biodiversity

New Research Substantiates DNA as an ‘Information Harboring’ Molecule

I always seem to wind up in the slowest checkout line at the grocery store. Experience has taught me that the shortest line is not always the fastest. I can never seem to avoid the insensitive and oblivious shopper who realizes that he has forgotten something and puts the cashier on hold (and everybody else in line behind him) while he disappears down an aisle to search for the overlooked item. Or the poor soul whose ATM card doesn’t work (and doesn’t work, and doesn’t work, swipe after swipe). Of course, there’s also the frustrating price check.

As sluggish as the checkout procedure can be at times, it could be worse. I am old enough to remember what shopping was like in the days before barcodes. The cashier had to examine the price sticker to get the cost of each item and then manually enter it into the cash register. In addition to being slow and cumbersome, this process was error-prone.

Barcodes have revolutionized the retail business. Now cashiers simply scan the items while computer technology does the rest. It has increased the speed and accuracy of the checkout process and provides the added benefit of giving the store managers a real-time inventory.

Scientists have come to realize that DNA can be used as a barcode to perform some of the same functions as barcodes printed onto food packaging. Biologists have been able to identify, catalog, and monitor animal species using relatively short, standardized segments of DNA within the genome that are unique to the species, or subspecies in some cases. And now new work extends the utility of DNA barcoding to plants.

Typically, barcodes harbor information in the form of parallel dark lines on a white background that create areas of high and low reflectance that can be read by a scanner and interpreted as binary numbers. Barcoding with DNA is possible because this biomolecule, at its essence, is an information-based system. In fact, DNA’s chief function in the cell is housing the information necessary to make all the proteins used by the cell.

The cell’s machinery forms the polynucleotide chains of DNA by linking together four different nucleotides, abbreviated A, G, C, and T. Just like the widths and spacings of barcodes, the sequence of nucleotides in the DNA strands represents information. (For example, the nucleotide sequence that specifies the production of a single protein chain is called a gene.)

In his book Information and the Origin of Life information theorist Bernd-Olaf Küppers points out that the structure of DNA’s information closely resembles the hierarchical organization of human language with nucleotides functioning as alphabet letters, and the genes like words, and so on.

One of the challenges of DNA barcoding centers on identifying a region within the genome that can distinguish a wide range of taxa. Researchers have recently discovered that the matK gene found in plastid DNA fulfills this requirement. This gene displays the so-called barcoding gap by simultaneously varying little within a species, but varying significantly between species. The matK sequence successfully discriminated over 1,000 orchid species of the Costa Rican rainforest and over 600 trees and shrubs of Kruger National Park in southern Africa, two of the world’s biodiversity hotspots. Barcoding with this gene even revealed the existence of cryptic species of orchids.

The matK gene should prove useful in developing biodiversity inventories. This DNA barcode can also help wildlife and customs agents stem the illegal transport and trade of endangered species, like some of the Costa Rican orchids. The matK barcode can even help identify the plant ingredients in traditional medicines, paving the way for biomedical advance.

The use of DNA as barcodes underscores the informational content of this biomolecule. DNA barcoding makes it clear that biochemical information is truly information.

Information serves as a potent marker for intelligent design. Human experience consistently teaches that information emanates from intelligence. Messages come from a mind. Information, in whatever form it takes, is not limited to communicating ideas, needs, and desires between human minds. It has even become an integral part of modern technology, as exemplified by barcoding technologies.

The information content of DNA, therefore, makes it rational to believe that life must have come from an intelligent agent, a Creator.

For more information on the exquisite design of living systems check out (no pun intended) my new book, The Cell’s Design.

Subjects: Biochemical Design, TCM - Biochemical Design

Dr. Fazale Rana

In 1999, I left my position in R&D at a Fortune 500 company to join Reasons to Believe because I felt the most important thing I could do as a scientist is to communicate to skeptics and believers alike the powerful scientific evidence—evidence that is being uncovered day after day—for God’s existence and the reliability of Scripture. Read more about Dr. Fazale Rana