aagctttatattgcatgtgtcttattgctttatattgagttcagttagtcacaagttgaacagagccaaggtaagagttcctttttactcttttcaagtttaagtggtggtttagctttccatctcgcatactcgtacattcaatgtactgatgccagtttgcctgcatcttattatgatgcagacacatgtacccagtatcagcatccagcacgccgttgatccagttgagcacttcagagtcagtggtgagcttctttgcatttcagaagactcggttattttgttctctttgttttgttttattaggatgttgtggggtctgtcccaacatccctcacaatattttagaggcttcatagacagtcagtcagttagttttgagtctctcatttatgtatatatgtaaatattctattttgagtctcgagttgccttttgggccagactttatgttgtttgttttataaccttgcattgcatggagttattctatgtgttaagtttccgctgagttaagaaagccaggccaagggttcgcttgggggccagcaatggtcttcgagtgccggccatgtccaaggtgtaggctcggggcgtgacaacttttcaaaggatttaacgatttaaatgaagcactaatctctcttgggccaaattatttcataagcccagctttaagacagtctttcctacaatacaatattcaaagggatactgacaggacatttctcttcaatgactgaaggattcaaaagactaaaccaactagagactgaaaagggaaaaatgacacaacatatccacgaatatggtttttacttggaaatactaatcaaaacataccattacaaatacaagactacccaaaaggacaaaagagttctccatctcatttcaaaatggataagacgggtgtacattccccaacgaatgtagagagagctattgtatcggctaaaggtacagctagtcctgcttaaacggtagcgggtaaagactcatcaaatccgttgatggatgacactttgccaaaaagtgtaaggattctgctagcaagtttcaatacagtggcagagacaagcaaaaaaataaagggattcctacaaaaaagaaaaaaaataaataataaaaagttccctttgcaagttacttaaaaaaaaactaaagaggttatacaagaaaaaattatacaagaaaacccaaacccagaaccaaaaccaacaaattctgatccagagtagaagtgatgagaacaatctatcaatagaccaatttactcgaatgaagacaatgattcaggaatgagtttcaattccgaacctggatacctaaagaaatacgtaagcaatgatgtcaacaagctatgacatcacaagccactactaaaaagaagactccactacctataaagaagattccactcctcagaaacggacaagaaaaaggacaattattttgaaaaaagtctttcaaaaccatgtgacgatgaggcccaaagagcacccgacattaaagaaagattattttcaacatttgaaattcgaacttcaaatccggatctactcctataaatagagaccatttgcaagaagagaaagatagagcgaagRE S EARCH Code of one potato chromosome now completely cracked There was good reason for a party in the Dutch agricultural knowledge town of Wageningen by the end of 2008. Chromosome number 5 – out of the 12 that the potato contains in total – was the first chromosome to be completely unravelled by Dutch scientists. During the mini symposium “Potato: crack the code”, Wageningen University presented the order of the building blocks of the chromosome in question: AAGCTTTATATTGCAT plus some 64 million AGC and Ts in the correct order. F or a number of years now, and together with fourteen other scientific institutes and universities, Wageningen University has been busy unravelling the order of the building blocks of the DNA in the potato. In scientific terms this is called genome sequencing: the determination of the order of bases (building blocks) in DNA strings. The order of the bases determines the characteristics of an organism. There are in total four bases: Adenine, Guanine, Cytosine and Thymine. There are also pieces in a chromosome, the bases of which have an equal order and this is called a gene. A gene is the carrier of specific information for a specific characteristic. Characteristics are, for example, the colour of the skin of a potato or Phytophthora resistance. The background of the pages of this article shows a very small piece of the recently found, long building-block order of chromosome no. 5 of the potato. All chromosomes mapped out in 2010 Professor Richard Visser explains once more why it is so important that it is the potato that is subjected to genome sequencing and how much work this takes. At this moment, after wheat and rice, the potato is the third most important food crop in the world. Policymakers, nutritionists and agricultural scientists would like the cultivation of potatoes to become more prominent throughout the world, particularly in countries that suffer from drought and famine. It is not without reason that the United Nations declared the year 2008 “the Year of the Potato”. In relation to cereals, for example, the potato can produce a great deal of dry matter with relatively little water and few nutrients. For an acceptable and profitable crop in dry and hot Director-General Annemie Burger of the Ministry of Agriculture, Nature Management and Food Quality hands the USB sticks to the researchers and the potato eaters of the countries, characteristics such as drought and stress resistance and rapid growth are important. In order to have these characteristics quickly available for new potato varieties, it is important, according to Professor Visser, that we understand the meaning of the recently-discovered sequence as soon as possible. The Wageningen scientists can only work now with the no. 5 chromosome, because the other 11 have not yet been cracked. Institutes and universities in other countries are currently working on the unravelling of the building block order of 10 other chromosomes; one chromosome is not yet being studied. It is to be expected that it will take at least until the year 2010 before we understand the entire genome of the potato. Professor Richard Visser explains that chromosome no. 5 out of the 12 that the potato contains in total was the first to be completely unravelled by Dutch scientists. All AGCTs on one USB stick How important it is that we know the code of the potato, has been explained again in simple terms on a USB stick, which the schoolchildren in Wageningen received from Director-General Annemie Burger of the Ministry of Agriculture, Nature Management and Food Quality. Researchers know already an awful lot about the potato, but a great deal is still not yet known. How is it possible, for example, that one potato falls ill and the other is well protected and is healthy? Getting the building block order straight may give an answer to that question. The information found in this way, helps potato breeders in developing new varieties. This may mean, for example, that we will be able to grow and process potatoes in an environmentally-friendly way. All this can be read in the information on the USB stick. ● Leo Hanse Potato World 2009 • number 1 19 Pagina 18

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