The Major Histocompatibility Complex contains highly polymorphic genes, which are critical in regulating the immune response. We have investigated MHC genes in a variety of wild canids, including Ethiopian wolves and African wild dogs. We also tested whether intronic primers designed for the domestic dog amplify MHC genes in other canids.

Previous data have shown that some DLA class II alleles are shared between the domestic dog and its ancestor, the Grey Wolf. However, it was not clear whether there would be allele sharing between any other canids and the domestic dog, see Table 1.

Sequence based typing (SBT) was used to characterise DLA haplotypes in 120 Ethiopian wolves. Eight haplotypes were identified, which included four DRB1, two DQA1 and five DQB1 alleles. One DQA1 and one DQB1 allele had previously been found in domestic dogs, and one DQB1 allele has previously been found in grey wolves, see Table 2.

SBT was used to characterise DLA alleles in 120 African wild dogs. We identified 18 DRB1, one DQA1 and two DQB1 alleles, none of which had previously been seen in domestic dogs, see Table 3.

Table 1: Allele Sharing between 175 North American Grey Wolves and >5000 Domestic Dogs

Table 2: Allele Sharing between 120 Ethiopian Wolves Grey Wolves and Domestic Dogs

Table 3: Allele Sharing between 120 African Wild Dogs, other Canids and Domestic Dogs

Screening a panel of canids using dog intronic primers revealed several different patterns of reactions. The data do not indicate whether a gene is present, but just whether the introns are similar enough to the domestic dog to allow amplification. DNA from maned wolf amplified with DRA and DQA1, while Kit Fox DNA amplified with DQA1 only. Arctic fox DNA also amplified DQA1, but has not been tested with the others yet. Two fox species were positive for all except DRB1 and the red fox was also negative for DRB1. Other canid DNAs, including grey wolf, Ethiopian wolf, African wild dog, Döhle, Bush dog and Arabian wolf, amplified with all four primer pairs.

Table 4: Amplification of MHC Genes in Other Canids Using Dog Primers

****SEE ORIGINAL TO COLOR TABLE CELLS*****

These data provide interesting additional information on how closely related these different canids may be.

Discussion

 Using dog intronic primers can help identify how closely related other canids are to the domestic dog

 The more distantly related a canid to the domestic dog or grey wolf, the more varied the MHC gene introns are, and the less likely their MHC genes will amplify with dog primers

 Exonic primers amplify DLA-DRB1 and DQB1 in the Arctic Fox, therefore these genes are not missing

 DLA-DQA1 and DQB1 appear to be more conserved than DLA-DRB1

 Other canids do not lack MHC genes, they have different intron sequences

 Closely related canids share alleles

 There is allele sharing between canids, but it reduces with evolutionary distance