# Gene density

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

| species | number of genes | base pairs in genome (Mb) | gene density |
| Babesia microti | 3,685 | 6.4 | 575.8 |
| Besnoitia besnoiti | 8,546 | 58.8 | 145.3 |
| Cryptosporidium parvum | 3,887 | 9.1 | 427.1 |
| Giardia intestinalis | 5,388 | 11.5 | 468.5 |
| Leishmania donovani | 8,123 | 32.4 | 250.7 |
| Plasmodium falciparum | 5,683 | 23.5 | 241.8 |
| Phytophthora infestans | 19,344 | 203.2 | 95.2 |
| Tetrahymena thermophila | 26,996 | 130.4 | 207 |
| Theileria parva | 4,141 | 8.3 | 498.9 |
| Toxoplasma gondii | 8,925 | 64.5 | 138.4 |
| Trypanosoma cruzi | 25,183 | 32.5 | 774.9 |

### Fungi

| species | number of genes | base pairs in genome (Mb) | gene density |
| Agaricus bisporus | 11,459 | 30.7 | 373.3 |
| Aspergillus nidulans | 9,586 | 30.6 | 313.3 |
| Aspergillus niger | 10,828 | 35.6 | 304.2 |
| Candida albicans | 6,263 | 14.7 | 426.1 |
| Cryptococcus neoformans | 7,004 | 18.6 | 376.5 |
| Debaryomyces hansenii | 6,495 | 12.1 | 536.8 |
| Encephalitozoon cuniculi | 2,029 | 2.3 | 882.2 |
| Eremothecium gossypii | 5,356 | 9.1 | 588.6 |
| Fusarium oxysporum | 21,354 | 52.4 | 407.5 |
| Kluyveromyces lactis | 5,335 | 10.6 | 503.3 |
| Lasiodiplodia theobromae | 13,054 | 43.6 | 299.4 |
| Neurospora crassa | 10,590 | 41.3 | 256.4 |
| Saccharomyces cerevisiae | 6,445 | 11.9 | 541.6 |
| Saccharomyces paradoxus | 5,840 | 12 | 486.6 |
| Schizosaccharomyces pombe | 6,974 | 12.8 | 544.8 |
| Talaromyces marneffei | 10,138 | 28.3 | 358.2 |
| Tremella mesenterica | 8,292 | 27.9 | 297.2 |
| Trichoderma harzianum | 14,294 | 40.7 | 351.2 |
| Trichophyton rubrum | 8,804 | 23.1 | 381.1 |
| Ustilago maydis | 6,909 | 19.9 | 347.2 |
| Wallemia ichthyophaga | 5,000 | 9.5 | 526.3 |
| Yarrowia lipolytica | 7,144 | 20.3 | 351.9 |

### Plants

| species | common name | number of genes | base pairs in genome (Mb) | gene density |
| Ananas comosus | pineapple | 25,758 | 382 | 67.4 |
| Arabidopsis thaliana | thale cress | 38,311 | 119 | 321.9 |
| Asparagus officinalis | asparagus | 32,237 | 1,187 | 27.2 |
| Brassica rapa | field mustard | 51,592 | 333 | 154.9 |
| Cannabis sativa | cannabis | 31,170 | 876 | 35.6 |
| Cajanus cajan | pigeon pea | 33,495 | 593 | 56.5 |
| Capsicum annuum | pepper | 41,729 | 2,909 | 14.3 |
| Coffea arabica | coffee | 56,902 | 1,094 | 52 |
| Glycine max | soybean | 59,905 | 995.7 | 60.2 |
| Juglans regia | English walnut | 37,996 | 634.7 | 59.9 |
| Nicotiana tabacum | tobacco | 74,273 | 3,734.2 | 19.9 |
| Olea europaea | olive | 47,911 | 1,316.7 | 36.4 |
| Oryza sativa | rice | 35,223 | 385 | 91.5 |
| Panicum hallii | grass | 31,528 | 511.6 | 61.6 |
| Physcomitrium patens | spreading earthmoss | 23,747 | 472 | 50.3 |
| Prunus dulcis | almond | 26,936 | 236.9 | 113.7 |
| Prunus persica | peach | 26,412 | 214.2 | 123.3 |
| Punica granatum | pomegrante | 29,281 | 308.4 | 94.9 |
| Rosa chinensis | rose | 40,349 | 513.9 | 78.5 |
| Solanum lycopersicum | tomato | 31,263 | 813 | 38.5 |
| Solanum tuberosum | potato | 33,606 | 760 | 44.2 |
| Theobroma cacao | cocoa | 24,957 | 335 | 74.5 |
| Zea mays | corn | 49,796 | 2,197 | 22.7 |

### Invertebrate

invertebrate species :
| species | common name | number of genes | base pairs in genome (Mb) | gene density |
| Aedes aegypti | yellow fever mosquito | 19,623 | 1,274 | 15.4 |
| Anopheles gambiae | African malaria mosquito | 13,247 | 250 | 53 |
| Apis mellifera | honey bee | 12,374 | 226 | 54.8 |
| Caenorhabditis elegans | C. elegans | 47,632 | 102 | 467 |
| Daphnia magna | water flea | 21,549 | 126 | 171 |
| Drosophila melanogaster | fruit fly | 17,868 | 137 | 130.4 |
| Hydra vulgaris | hydra | 22,980 | 1,055 | 21.8 |
| Limulus polyphemus | horseshoe crab | 27,318 | 1,828 | 14.9 |
| Octopus sinensis | octopus | 29,784 | 2,719 | 11 |
| Pediculus humanus | human louse | 10,993 | 110 | 99.9 |
| Strongylocentrotus purpuratus | purple sea urchin | 33,504 | 921 | 36.4 |

### Vertebrate non-mammals

| species | common name | number of genes | base pairs in genome (Mb) | gene density |
| Alligator mississippiensis | American alligator | 25,279 | 2,161 | 11.7 |
| Anolis carolinensis | anole lizard | 22,293 | 1,799 | 12.4 |
| Astyanax mexicanus | Mexican tetra | 31,695 | 1,263 | 25.1 |
| Columba livia | pigeon | 26,679 | 1,063 | 25.1 |
| Danio rerio | zebrafish | 47,350 | 1,408 | 33.6 |
| Gallus gallus | chicken | 24,402 | 1,043 | 23.4 |
| Nothobranchius furzeri | turquoise killifish | 25,387 | 1,052 | 24.1 |
| Oryzias latipes | Japanese rice fish | 26,846 | 746 | 36 |
| Petromyzon marinus | sea lamprey | 22,167 | 987 | 22.5 |
| Taeniopygia guttata | zebra finch | 21,543 | 1,069 | 20.2 |
| Takifugu rubripes | Japanese puffer | 27,413 | 384 | 71.8 |
| Xenopus tropicalis | tropical clawed frog | 28,863 | 1,468 | 19.7 |
| Xenopus laevis | African clawed frog | 37,283 | 2,718 | 13.7 |

### Vertebrate mammals

| species | common name | number of genes | base pairs in genome (Mb) | gene density |
| Acinonyx jubatus | cheetah | 34,482 | 2,378 | 14.5 |
| Ailuropoda melanoleuca | giant panda | 32,950 | 2,371 | 13.9 |
| Aotus nancymaae | night monkey | 31,331 | 2,861 | 11 |
| Artibeus jamaicensis | Jamaican fruit-eating bat | 31,480 | 2,316 | 13.6 |
| Arvicanthis niloticus | African grass rat | 31,912 | 2,496 | 12.8 |
| Balaenoptera acutorostrata | minke whale | 26,805 | 2,431 | 11 |
| Balaenoptera musculus | blue whale | 27,194 | 2,105 | 12.9 |
| Bison bison | American bison | 27,488 | 2,828 | 9.7 |
| Bos mutus | wild yak | 26,159 | 2,703 | 9.7 |
| Bos taurus | cattle | 35,061 | 2,715 | 12.9 |
| Canis lupus familiaris | dog | 36,717 | 2,370 | 15.5 |
| Chinchilla lanigera | long-tailed chinchilla | 30,378 | 2,390 | 12.7 |
| Felis catus | cat | 35,521 | 2,521 | 14 |
| Gorilla gorilla | gorilla | 35,419 | 3,063 | 11.6 |
| Homo sapiens | human | 44,507 | 2,861 | 15.5 |
| Macaca mulatta | Rhesus monkey | 40,164 | 2,970 | 13.5 |
| Mus musculus | house mouse | 42,823 | 2,689 | 15.9 |
| Pan troglodytes | chimpanzee | 40,769 | 3,050 | 13.4 |
| Rattus norvegicus | brown rat | 38,371 | 2,743 | 14 |
| Sus scrofa | pig | 30,345 | 2,459 | 12.3 |
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.