The "hot five" biological articles of 2009
Which scientific articles have caused the greatest resonance this year? The ScienceWatch website, which tracks and analyzes trends in fundamental research, compiles a list of the 10 most frequently cited articles every two weeks. The Scientist experts selected from these lists the five most frequently cited articles on biology in 2009, published in 2007-2008. As expected, the most interesting topics for the scientific and general public this year were genomics and stem cells.
5. A. M. Wernig et al., «In vitro reprogramming of fibroblasts into a pluripotent ES-cell-like state», Nature 448: 318-24, 2007.
The researchers successfully carried out the transfer of the somatic cell nucleus to create stem cell lines and for the first time cloned animals from fertilized mouse eggs. According to ScienceWatch, this article was among the ten most cited scientific articles in 2009.
Number of citations in 2009: 237
Total citations at the end of 2009: 512
4. E. Birney et al., «Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project», Nature, 447: 799-816, 2007.
As part of the ENCODE (ENCyclopedia Of DNA Elements) project, specialists begin work on the identification of all functional elements of the human genome. The study of 1% of the genome provided scientists with new data on how the information encoded in DNA is transformed into the processes taking place in the cell.
Number of citations in 2009: 267
Total citations at the end of 2009: 618
3. A. Barski et al., «High-resolution profiling of histone methylations in the human genome», Cell, 129: 823-37, 2007.
The authors studied the effect of histone modifications on gene expression in more detail than was previously possible. Using a powerful Solexa 1G sequencing tool, they mapped more than 20 million DNA sequences associated with specific histone forms. As a result, differences in the patterns of DNA methylation of stem cells and differentiated T-lymphocytes were identified.
Number of citations in 2009: 299
Total citations at the end of 2009: 560
2. K. A. Frazer et al., «A second generation human haplotype map of over 3.1 million SNPs», Nature, 449: 854-61, 2007.
After sequencing the human genome in 2003 within the framework of the international HapMap project, researchers continued to study single nucleotide polymorphisms, or "snips" (from the English single nucleotide polymorphisms, SNP) – differences in single nucleotide bases of DNA – and their impact on the likelihood of developing various diseases, drug metabolism and the body's response to a meeting with pathogens. At the time of writing the first report on the work done by HapMap I, the project executors identified approximately one snip for every 5,000 DNA nucleotide bases. The latest DNA map published in this article contains 2 million additional snips, which increases the resolution of the map to one snip per kilobase (1,000 nucleotide bases). This additional information allows researchers to study in more detail the patterns of distribution of snips, especially in the "hot" regions of DNA.
Number of citations in 2009: 389
Total citations at the end of 2009: 588
1. K. Takahashi et al., «Induction of pluripotent stem cells from adult human fibroblasts by defined factors», Cell, 131: 861-72, 2007.
Japanese scientists from the Shinya Yamanaka laboratory have demonstrated for the first time the possibility of converting adult human skin fibroblasts into induced pluripotent stem cells (iPSCs). Previously, the same authors used somatic cells of mice to obtain iPSCs. According to ScienceWatch, this work was the most cited in the outgoing year.
Number of citations in 2009: 520
Total citations at the end of 2009: 886