Top journals in molecular biology and genetics based on total citations

	Journal	Papers	Citations	Citations per paper
1	Cell	3,824	552,923	144.59
2	Science	1,353	179,561	132.71
3	Nature	1,695	224,1	132.31
4	Nature Genetics	2,244	254,603	113.46
5	Nature Reviews Molecular Cell Biology	613	56,838	92.72
6	Genes & Development	3,105	255,862	82.40
7	Current Opinion in Cell Biology	1,009	80,893	80.17
8	Nature Cell Biology	1,464	94,734	64.71
9	Molecular and Cellular Biology	2,632	165,074	62.72
10	Journal of Cell Biology	4,879	293,060	60.07
11	EMBO Journal	6,675	393,721	58.98
12	Trends in Cell Biology	868	50,606	58.30
13	American Journal of Human Genetics	3,048	147,829	48.50
14	Development	5,4	225,293	41.51
15	Genome Research	2,011	79,314	39.44
16	Proceedings of the Nat Acad of the USA	5,260	203,904	38.77
17	Molecular and Cellular Biology	8,932	342,288	38.32
18	Human Molecular Genetics	3,589	129,823	36.17
19	Human Gene Therapy	1,903	54,307	28.54
20	Molecular Biology of the Cell	3,995	113,099	28.31

This ranking should be recognised as distinctly different from Thomson Scientific’s impact factor rankings, which are presented in the Journal Citation Reports issued each year. The impact factor is calculated as citations in Year 3 to a journal’s contents in Years 1 and 2, divided by the number of so-called citable items (regular articles and reviews) in Years 1 and 2. Thus, the above ranking reveals longer-term impact (citations per paper). The data for the multidisciplinary journals listed – Science, Nature and the Proceedings of the National Academy of the USA – take into account only those articles that have been classified by Thomson Scientific as molecular biology and genetics papers.

The data above were extracted from Thomson Scientific’s Essential Science Indicators database. This database, currently covering the period January 1997 to December 2007, surveys only journal articles (original research reports and review articles) indexed by Thomson Scientific. Articles are assigned to a category based on the journals in which they were published and Thomson Scientific’s journal-to-category field definition scheme. Both articles tabulated and citation counts to those articles are for the period indicated. Here our ranking of journals in molecular biology and genetics is by citations per paper, among journals that collected 50,000 or more citations, to reveal weighted impact. Essential Science Indicators lists journals ranked in the top 50 per cent for a field over a given period, based on total citations. In molecular biology and genetics, 135 journals are listed, meaning 0 journals in this field were surveyed. Thirty journals earned at least 50,000 citations.

For more information on Thomson Scientific’s Essential Science Indicators, see http://scientific.thomson.com/products/esi. For more information on Thomson Scientific, see http://scientific.thomson.com.