In genetics, the gene density of an organism's genome is the ratio of the number of genes per number of base pairs, usually written in terms of a million base pairs, or megabase (Mb). The human genome has a gene density of 11-15 genes/Mb, while the genome of the C. elegans roundworm is estimated to have 200.

Seemingly simple organisms, such as bacteria and amoebas, have a much higher gene density than humans. Bacterial DNA has a gene density on the order of 500-1000 genes/Mb. This is due several factors, including that the fact that bacterial DNA has no introns. There are also fewer codons in bacterial genes.

Species

Protozoa +speciesnumber of genesbase pairs in genome (Mb)gene densityBabesia microti3,6856.4575.8Besnoitia besnoiti8,54658.8145.3Cryptosporidium parvum3,8879.1427.1Giardia intestinalis5,38811.5468.5Leishmania donovani8,12332.4250.7Plasmodium falciparum5,68323.5241.8Phytophthora infestans19,344203.295.2Tetrahymena thermophila26,996130.4207Theileria parva4,1418.3498.9Toxoplasma gondii8,92564.5138.4Trypanosoma cruzi25,18332.5774.9

Fungi +speciesnumber of genesbase pairs in genome (Mb)gene densityAgaricus bisporus11,45930.7373.3Aspergillus nidulans9,58630.6313.3Aspergillus niger10,82835.6304.2Candida albicans6,26314.7426.1Cryptococcus neoformans7,00418.6376.5Debaryomyces hansenii6,49512.1536.8Encephalitozoon cuniculi2,0292.3882.2Eremothecium gossypii5,3569.1588.6Fusarium oxysporum21,35452.4407.5Kluyveromyces lactis5,33510.6503.3Lasiodiplodia theobromae13,05443.6299.4Neurospora crassa10,59041.3256.4Saccharomyces cerevisiae6,44511.9541.6Saccharomyces paradoxus5,84012486.6Schizosaccharomyces pombe6,97412.8544.8Talaromyces marneffei10,13828.3358.2Tremella mesenterica8,29227.9297.2Trichoderma harzianum14,29440.7351.2Trichophyton rubrum8,80423.1381.1Ustilago maydis6,90919.9347.2Wallemia ichthyophaga5,0009.5526.3Yarrowia lipolytica7,14420.3351.9

Plants +speciescommon namenumber of genesbase pairs in genome (Mb)gene densityAnanas comosuspineapple25,75838267.4Arabidopsis thalianathale cress38,311119321.9Asparagus officinalisasparagus32,2371,18727.2Brassica rapafield mustard51,592333154.9Cannabis sativacannabis31,17087635.6Cajanus cajanpigeon pea33,49559356.5Capsicum annuumpepper41,7292,90914.3Coffea arabicacoffee56,9021,094 52Glycine maxsoybean59,905995.760.2Juglans regiaEnglish walnut37,996634.759.9Nicotiana tabacumtobacco74,2733,734.219.9Olea europaeaolive47,9111,316.736.4Oryza sativarice35,22338591.5Panicum halliigrass31,528511.661.6Physcomitrium patensspreading earthmoss23,74747250.3Prunus dulcisalmond26,936236.9113.7Prunus persicapeach26,412214.2123.3Punica granatumpomegrante29,281308.494.9Rosa chinensisrose40,349513.978.5Solanum lycopersicumtomato31,26381338.5Solanum tuberosum potato33,60676044.2Theobroma cacaococoa24,95733574.5Zea mays corn49,7962,19722.7

Invertebrate +invertebrate speciesspeciescommon namenumber of genesbase pairs in genome (Mb)gene densityAedes aegyptiyellow fever mosquito19,6231,27415.4Anopheles gambiaeAfrican malaria mosquito13,24725053Apis melliferahoney bee12,37422654.8Caenorhabditis elegansC. elegans47,632102467Daphnia magnawater flea21,549126171Drosophila melanogasterfruit fly17,868137130.4Hydra vulgarishydra22,9801,05521.8Limulus polyphemushorseshoe crab27,3181,82814.9Octopus sinensisoctopus29,7842,71911Pediculus humanushuman louse10,99311099.9Strongylocentrotus purpuratuspurple sea urchin33,50492136.4

Vertebrate non-mammals +speciescommon namenumber of genesbase pairs in genome (Mb)gene densityAlligator mississippiensisAmerican alligator25,2792,16111.7Anolis carolinensisanole lizard22,2931,79912.4Astyanax mexicanusMexican tetra31,6951,26325.1Columba liviapigeon26,6791,06325.1Danio reriozebrafish47,3501,40833.6Gallus galluschicken24,4021,043 23.4Nothobranchius furzeriturquoise killifish25,3871,05224.1Oryzias latipesJapanese rice fish26,84674636Petromyzon marinussea lamprey22,16798722.5Taeniopygia guttatazebra finch21,5431,06920.2Takifugu rubripesJapanese puffer27,41338471.8Xenopus tropicalistropical clawed frog28,8631,46819.7Xenopus laevisAfrican clawed frog37,2832,71813.7

Vertebrate mammals +speciescommon namenumber of genesbase pairs in genome (Mb)gene densityAcinonyx jubatuscheetah34,4822,37814.5Ailuropoda melanoleucagiant panda32,9502,37113.9Aotus nancymaaenight monkey31,3312,86111Artibeus jamaicensisJamaican fruit-eating bat31,4802,31613.6Arvicanthis niloticusAfrican grass rat31,9122,49612.8Balaenoptera acutorostrataminke whale26,8052,43111Balaenoptera musculusblue whale27,1942,10512.9Bison bisonAmerican bison27,4882,8289.7Bos mutuswild yak26,1592,7039.7Bos tauruscattle35,0612,71512.9Canis lupus familiarisdog36,7172,37015.5Chinchilla lanigeralong-tailed chinchilla30,3782,39012.7Felis catuscat35,5212,52114Gorilla gorilla gorilla35,4193,06311.6Homo sapienshuman44,5072,86115.5Macaca mulattaRhesus monkey40,1642,97013.5Mus musculushouse mouse42,8232,68915.9Pan troglodyteschimpanzee40,7693,05013.4Rattus norvegicusbrown rat38,3712,74314Sus scrofapig30,3452,45912.3 Gene count is calculated by the number of gene flags in the latest version of a given species gtf annotation file. Bear in mind that well studied organisms will probably have higher gene counts because these species have better annotation, therefore these numbers are estimates for comparison.

See also C-value enigma

References