April 1, 1998

Mammals have 15 P450 families and 29 subfamilies

 1) CYP1     with 2 subfamilies 1A and 1B
 2) CYP2     with 8 mammalian subfamilies 2A, 2B, 2C, 2D, 2E, 2F, 2G and 2J
 3) CYP3     with 1 subfamily 3A
 4) CYP4     with 3 mammlian subfamilies 4A, 4B and 4F
 5) CYP5     with 1 subfamily and only one sequence
 6) CYP7     with 2 subfamilies 7A and 7B
 7) CYP8     with 2 subfamilies 8A and 8B
 8) CYP11    with 2 subfamilies 11A and 11B
 9) CYP17    with 1 subfamily and only one sequence
10) CYP19    with 1 subfamily and only one sequence
11) CYP21    with 1 subfamily
12) CYP24    with 1 subfamily and only one sequence
13) CYP26    with 1 subfamily and only one sequence
14) CYP27    with 2 subfamilies 27A and 27B and two sequences
16) CYP51    with 1 subfamily and only one sequence

The number of individual genes in a given species is given below.

RATS have 60 sequenced CYP genes and 4 pseudogenes
  1A1, 1A2, 1B1, 2A1, 2A2, 2A3, 2B1, 2B2, 2B3, 2B8, 2B12, 2B14, 2B15, 2B16P, 
2C6, 2C6P, 2C7, 2C11, 2C12, 2C13, 2C22, 2C23, 2C24, 2D1, 2D2, 2D3, 2D4, 2D5, 
2D18, 2E1, 2G1, 2J3, 2J3P1, 3J3P2, 2J4, 3A1, 3A2, 3A9, 3A18, 3A23, 4A1, 4A2, 
4A3, 4A8, 4B1, 4F1, 4F4, 4F5, 4F6, 5A1, 7A1, 7B1, 8A1, 11A1, 11B1, 11B2, 11B3, 
17, 19, 21, 24, 27A, 27B, 51

The following have not been sequenced in rats 8B, 26.
If these are found in rats, they will have at least 62 CYP genes and 4 pseudogenes.

HUMANS have 36 sequenced CYP genes and 10 pseudogenes.
  1A1, 1A2, 1B1, 2A6, 2A7, 2A7PT (telomeric), 2A7PC(centromeric), 2A13, 2B6, 2B7P, 
2C8, 2C9, 2C18, 2C19, 2D6, 2D7P, 2D7AP, 2D8P, 2D8BP, 2E1, 2F1, 2F1P, 
2J2, 3A4, 3A5, 3A5P, 3A7, 4A11, 4B1, 4F2, 4F3, 5A1, 7A1, 8A1, 11A1, 
11B1, 11B2, 17, 19, 21A1P, 21A2, 24, 26, 27A1, 27B1, 51

2C10, 3A3 and 4A9 have been removed because they are probably artifacts.
The following have not yet been sequenced in humans 2G, 7B, 8B.
If these are found in humans, they will have at least 39 CYP genes and 10 pseudogenes.

MICE have 45 sequenced CYP genes and 1 pseudogene.
  1a1, 1a2, 1b1, 2a4, 2a5, 2a12, 2b9, 2b10, 2b13, 2b19, 2b20, 2c29, 2c37, 2c38, 2c39, 
2c40, 2d9, 2d10, 2d11, 2d12, 2d13, 2e1, 2f2, 2g1, 2j5, 2j6, 3a11, 3a13, 3a16, 3a25, 
4a10, 4a12, 4a14, 4b1, 5a1, 7a1, 7b1, 8a1, 11b1, 11b2, 17, 19, 21a1, 21a2p, 26, 27b

The following have not been sequenced in mice 8b, 11a, 24, 27a, 51.
If these are found in mice, they will have at least 50 CYP genes and 1 pseudogene. 

RABBITS have 32 sequenced CYP genes and no pseudogenes.
  1A1, 1A2, 2A10, 2A11, 2B4, 2B5, 2C1, 2C2, 2C3, 2C4, 2C5, 2C14, 2C15, 2C16, 
2C30, 2D23, 2D24, 2E1, 2E2, 2G1, 2J1, 3A6, 4A4, 4A5, 4A6, 4A7, 4B1, 7A1, 8B1, 
11A1, 19, 27.

The following have not been sequenced in rabbits 1B, 2F, 4F, 5, 7B, 8A, 11B, 17,
 21, 24, 26, 27B, 51.
If these are found in rabbits, they will have at least 45 CYP genes.

The following mammalian species have many fewer genes sequenced, and these species 
should probably not be the focus of additional sequencing effort.

Hamster     15 genes 1A1, 1A2, 2A8, 2A9, 2C25, 2C26, 2C27, 2C28, 2D20, 2E1, 3A10, 
                                  7A1,11B1, 11B2, 17
Pig          14 genes 2C32, 2C33, 2C34, 2C35, 2C36, 2C42, 2C42P1, 5A1, 3A29, 11A1, 
                                  11B1, 17, 19, 21
Guinea pig   11 genes 1A1, 1A2, 2B18, 2D16, 3A14, 3A15, 3A17, 3A20, 4A13, 
                                   11B1, 17
Bovine      10 genes  2D14, 3A28, 8A1,11A1,11B1,11B2,11B4,17,19,21
Monkeys      8 genes 1A1, 2B17, 2C20, 2C37, 2D17, 2E1, 3A8, 19
Dog          8 genes 1A1, 1A2, 2B11, 2C21, 2C41, 2D15, 3A12, 3A26
Sheep        6 genes 1A1, 11A1, 11B1, 17, 21, 3A24, 
Goat         3 genes 2C31, 3A19, 11A1
Horse        2 genes 17, 19
Baboon       3 gene fragments 11B1, 2A, 3A


The insect sequences that have been done recently show that one species, Anopheles 
albimanus (a mosquito) has at least 17 CYP genes and this is certain to increase.  
4C2, 4D5, 4D6, 4D7, 4H1, 4H2, 4H3, 4H4, 4H5, 4H6, 4H7, 4H8, 4H9, 4J1, 4J2, 4J3,
 4K1

Drosophila melanogaster has at least 17 CYP genes 
4c3, 4d1, 4d2, 4d8, 4e1, 4e2, 4e3, 4e4, 4g1, 4p1, 6a2, 6a8, 6a9, 9b1, 9b2, 9c1, 18

Musca domestica (the housefly) has at least 16 CYP genes.
4D3, 4D4, 4D9, 4G2, 4G3, 4N1, 4N2, 6A1, 6A3, 6A4, 6A5, 6A6, 6A7, 6C1, 6C2, 6D1

The nematode worm C. elegans was recently shown to have a gene cluster of 8 CYP genes 
and one pseudogene, all found on one cosmid T10B9.  An additional gene was sequenced 
that belongs to this family (CYP13A10) There are currently 80 known genes in C. elegans.
For details see this list 
For the actual Protein sequences see this file 

Yeast has only three CYP genes CYP51, CYP56 and CYP61.

Candida tropicalis has 8 CYP genes.  

Arabidopsis has at least 51 CYP genes.
For a summary see this list 
For a list of ESTs see this table 

Zea mays (maize) has 17 CYP genes in 8 different families.

Eggplant has 8 CYP genes in 4 different families.  

So far 30 families have been designated in plants.  These are not as clearly 
segregated as in animals and it is much more difficult to assign nomenclature to plant 
sequences due to the close clustering of the different families. 
Since Plants use P450s to sythesize hormones and other complex chemicals, plants may
have more P450 genes than mammals.  It will be some time before a large enough sample
of plant sequences is available to estimate if most plant families are represented.  At the
present time many new plant sequences fall into new families.  This will probably continue
for some time.  

Among the bacterial sequences, Streptomyces has 8 CYP genes, however the real surprise 
in bacterial P450s is Mycobacterium tuberculosis with al least 11 P450 genes, more than 
ony other bacterial species.