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PRD Class
Families List  Genes List
The PRD class is the second largest of the homeobox gene classes in animal genomes; like the ANTP class these genes have only been found in animals. The PRD class derives its name from (but is not an abbreviation for) the Paired (Prd) gene of Drosophila. PRD class genes are defined phylogenetically - they form a robust monophyletic group in evolutionary trees of homeodomain sequences. The PRD homeobox class overlaps with the Pax gene class - some but not all Pax genes are in the PRD homeobox gene class, while the vast majority of PRD class homeobox genes are not Pax genes.

There are 9 Pax genes in the human or mouse genomes, defined by presence of a 128 amino acid Paired domain, and of these 7 are members of the PRD homeobox class by virtue of possessing a homeobox: complete homeobox for PAX3, 4, 6 and 7; partial homeobox for PAX2, 5 and 8 (the two human Pax genes lacking a homeobox entirely are PAX1 and PAX9; these are not included in this database). In addition to these 7 homeobox-containing Pax genes, there are a further 43 PRD class genes in the human genome. These 50 genes can be divided into 31 gene families. There are also 24 human pseudogenes generated from these genes, plus an unknown number of DUX repetitive sequences (Holland et al. 2007).

In amphioxus there are 5 Pax genes, and of these 3 are have a partial or complete homeobox (Pax-1/9 and Pon are the two lacking homeobox sequence and therefore excluded; Pon is present in Drosophila and amphioxus, but not human). In addition to these genes, there are a further 27 PRD class genes in amphioxus (Takatori et al. 2008).

Reference(s):
Holland PWH, Booth HAF, Bruford EA (2007) BMC Biology 5:47.
Takatori N et al (2008) Dev Genes Evol 218: 579-590.
 
Families List of Class PRD :
Alx(1)AprdA(1)AprdB(1)AprdC(1)AprdD(2)AprdE(1)Arx(1)Dmbx(1)Drgx(1)
Gsc(1)Hopx(1)Isx(1)Otp(1)Otx(1)Pax2/5/8(1)Pax3/7(1)Pax4/6(1)Phox(1)
Pitx(1)Prop(1)Prrx(1)Rax(1)Repo(1)Shox(1)Uncx(3)Vsx(1)  
 
Loci in PRD of Amphioxus back to top..
Symbol/LocusNameFamilyOrganismRegulator
AlxAlxAlxAmphioxus 
Aprd1Aprd1AprdAAmphioxus 
Aprd2Aprd2AprdBAmphioxus 
Aprd3Aprd3AprdCAmphioxus 
Aprd4Aprd4AprdDAmphioxus 
Aprd5Aprd5AprdDAmphioxus 
Aprd6Aprd6AprdEAmphioxus 
ArxArxArxAmphioxus 
DmbxDmbxDmbxAmphioxus 
DrgxDrgxDrgxAmphioxus 
GscGscGscAmphioxus 
HopxHopxHopxAmphioxus 
IsxIsxIsxAmphioxus 
OtpOtpOtpAmphioxus 
OtxOtxOtxAmphioxus 
Pax2/5/8Pax2/5/8Pax2/5/8Amphioxus 
Pax3/7Pax3/7Pax3/7Amphioxus 
Pax6Pax6Pax4/6Amphioxus 
PhoxPhoxPhoxAmphioxus 
PitxPitxPitxAmphioxus 
PropPropPropAmphioxus 
PrrxPrrxPrrxAmphioxus 
RaxRaxRaxAmphioxus 
RepoRepoRepoAmphioxus 
ShoxShoxShoxAmphioxus 
UncxAUncxAUncxAmphioxus 
UncxBUncxBUncxAmphioxus 
UncxCUncxCUncxAmphioxus 
VsxVsxVsxAmphioxus