Allelic Variation at theVHaLocus in Natural Populations of Rabbit (Oryctolagus cuniculus, L.)

Abstract

The large interallelic distances between the three rabbit Ig V(H)a lineages, a1, a2 and a3, suggest that the persistence time of the V(H)a polymorphism could amount to 50 million years, which is much longer than that of MHC polymorphisms. Rabbit originated in the Iberian Peninsula where two subspecies coexist, one of which is confined to Southwestern Iberia (Oryctolagus cuniculus algirus). We studied the V(H) loci in the original species range to obtain a better understanding of the evolutionary history of this unusual polymorphism. Serological surveys revealed that sera from the subspecies algirus, when tested with V(H)a locus-specific alloantisera, showed either cross-reactivity ("a-positive" variants) or no reaction at all ("a-blank"). Using RT-PCR, we determined 120 sequences of rearranged V(H) genes expressed in seven algirus rabbits that were typed as either a-positive or a-blank. The data show that the V(H) genes transcribed in a-positive rabbits are closely related to the V(H)1 alleles of domestic rabbits. In contrast, a-blank rabbits were found to preferentially use V(H) genes that, although clearly related to the known V(H)a genes, define a new major allotypic lineage, designated a4. The a4 sequences have hallmark rabbit V(H)a residues together with a number of unprecedented amino acid changes in framework region 2 and 3. The net protein distances between the V(H)a4 and the V(H)a1, a2, and a3 lineages were 20, 29, and 21% respectively. We conclude that at least four distantly related lineages of the rabbit V(H)a locus exist, one of which seems to be endemic in the Iberian range.

Insights into the European rabbit (Oryctolagus cuniculus) innate immune system: genetic diversity of the toll-like receptor 3 (TLR3) in wild populations and domestic breeds

“…The higher variability in the wild populations may be due to the absence of man-mediated selection and a greater exposure to pathogens. Additionally, the low genetic diversity observed for the French populations when comparing with the IP populations might be explained because they are a subsample of the Iberian OCC which has recently colonised France [20,25,26]. …”

Histo-Blood Group Antigens Act as Attachment Factors of Rabbit Hemorrhagic Disease Virus Infection in a Virus Strain-Dependent Manner

“…The uniquely strong binding of G1, a strain restricted to the Iberian Peninsula, to Le y suggests an important role of the host genetic background. G1 is the only genetic group present in that region, a fact that might be correlated with the Pyrenees acting as a barrier to the dispersal of both the virus and rabbits, but also by the fact that the European rabbit originated in that area and that populations of other parts of the world consist of only a subset of that original gene pool [26], [27], [28], . The higher genetic diversity of the Iberian rabbits may be reflected in the need of the virus to explore other carbohydrates for binding.…”

mtDNA diversity in a rabbit population from Sicily (Italy)

“…In a more recent study, rabbits from the island of Mallorca were identified as belonging to O. c. cuniculus, having origins from Iberian and French populations (Seixas et al, 2014). Instead, the IP population in the northeast was regarded as O. c. cuniculus, whereas populations in the southwest of the IP, North Africa, the Mediterranean islands (including Sicily), and the Portuguese Atlantic islands were considered as O. c. algirus (Branco et al, 2000;Esteves et al, 2004). All other introduced populations and domesticated varieties were considered to be descendants of the nominate subspecies Branco et al, 2000;Branco and Ferrand, 2003).…”