Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Between a chicken and a grape: estimating the number of human genes. | Pertea and Salzberg Genome Biology 2010 11 206 http 2010 11 5 206 w Genome Biology REVIEW L_ Between a ehieken and a grape estimating the number of human genes Mihaela Pertea and Steven L Salzberg Abstract Many people expected the question How many genes in the human genome to be resolved with the publication of the genome sequence in 2001 but estimates continue to fluctuate. Ever since the discovery of the genetic code scientists have been trying to catalog all the genes in the human genome. Over the years the best estimate of the number of human genes has grown steadily smaller but we still do not have an accurate count. Here we review the history of efforts to establish the human gene count and present the current best estimates. The first attempt to estimate the number of genes in the human genome appeared more than 45 years ago while the genetic code was still being deciphered. Friedrich Vogel published his preliminary estimate in 1964 1 based on the number of amino acids in the alpha- and beta-chains of hemoglobin 141 and 146 respectively . Knowing that three nucleotides corresponded to each amino acid he extrapolated to compute the molecular weight of the DNA comprising these genes. He then made several assumptions in order to produce his estimate that these proteins were typical in size they are actually smaller than average that nucleotide sequences were uninterrupted on the chromosomes introns were discovered more than 10 years later 2 3 and that the entire genome was protein coding. All these assumptions were reasonable at the time but later discoveries would reveal that none of them was correct. Vogel then used the molecular weight of the human haploid chromosomes to correctly calculate the genome size as 3 X 109 nucleotides and dividing that by the size of a typical gene came up with an estimate of million genes. Correspondence salzberg@ Center for Bioinformatics and Computational Biology University of Maryland .
