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Unformatted text preview: need for a cutoff derived from the fact that about 260,000 ORFs were identified assuming a length of 2–99 amino acids (Fig. A.5). Using the arbitrary cutoff of 100 amino acids, the genome contains 7505 ORFs that potentially code for proteins. However, the cutoff is useful only as an approximation. Two hundred ten ORFs less than 100 amino acids in length now appear to code for proteins and a substantial number of ORFs greater than 100 amino acids in length may not code for proteins. Thus, since the completion of the yeast genome project in 1996, it is still not possible to say exactly how many protein-coding genes exist in yeast. The number is likely to be between 6000 and 6500 genes. Among the protein products of these genes, about 2000 have no known function, have not been identified by genetic or biochemical approaches, and share no sequence similarity to other characterized proteins. Among the protein-coding genes, introns occur in only 4% to 5% of all yeast genes (276 genes contain a single intron and 7 genes contain two separate intro...
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This note was uploaded on 10/03/2013 for the course BI 206 taught by Professor Celenza during the Spring '08 term at BU.

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