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The First Plant SequencedThe First Plant Sequenced

Scientists have been studying the genomes of living things for years, but, when it came to deciphering what different genes do, they had been using a mapThe relative positions of genes on a DNA molecule with very few landmarks. That is, until recently... In the past decade scientists have developed the tools to become genetic mapmakers. It’s a process called gene sequencingThe scientific reading of an organism’s genetic code, identifying all the base pairs and determining their order in the genome and, for the first time, scientists are able to identify all the genetic addresses and plot them out into a map.

The first plant to be sequenced is a little weed from the mustard family called ArabidopsisThe first plant to have its genome completely sequenced and mapped. A member of the mustard family, Arabidopsis thaliana, more commonly known as “mouse-eared cress” is a fast growing weed used in countless biological research facilities because of it relatively small and simple genome. thaliana—more commonly known as the “mouse-eared cress”.

Sequencing a genome means you identify—in order—every miniscule piece (or nucleotideThe basic unit of DNA and RNA. It consists of one chemical base, a phosphate group, and a sugar molecule. Adenine, guanine, thymine, and cytosine are nucleotides.) in a plant’s genome. A genome is the complete genetic information of any living thing. It is the tiny blueprint found in the nucleusThe structure inside a cell that is essential to such cell functions as growth, metabolism, and reproduction of pretty much every cellThe fundamental microscopic unit of which all living things—except viruses—are composed, and it gives a plant all of the instructions it needs to be fruitful and multiply—when to bud, bloom, sleep or seed.

The Arabidopsis plant was the perfect candidate for the first genome to be sequenced, because it “only” has 25,000 genes. With such a stripped down genetic map, Arabidopsis can be used to compare information with plants that have bigger, more complex genomes. The entire Arabidopsis genome is available to researchers free of charge online.

If you were to read a printout of genome sequence, you would see an impossibly long string of the letters A-T-C-GSymbols for adenine, thymine, cytosine, and guanine, the bases that pair up on a strand of DNA (called “base pairs”) and make up genes (which stand for the chemicals adenine, thymine, cytosine and guanine) in every imaginable combination. How do scientists make any sense of it?

They turn to computers and “bioinformatics”—a scientific field so new that it does not have a standard definition—but bioinformatics has completely changed the way that scientists investigate genomes. Basically, bioinformatics is the combination of molecular biology, computer science and information technology. Using powerful new search tools, genome scientists can blast through mountains of genetic data to find where on a chromosomeThe structure in a cell's nucleus that contains DNA; human cells have 46 chromosomes each (23 from each parent) a particular gene is located and what that gene can do.

Right now, scientists are working on a worldwide project to figure out the function of each and every Arabidopsis gene by the year 2010. Even this tiny genome takes scientists years of intense research to decode.