Haplotype structures and polymorphisms of dog leukocyte antigen (DLA) class I shaped by intralocus and interlocus recombination events

Jiro Miyamae*, Masaharu Okano, Kohei Nishiya, Fumihiko Katakura, Jerzy K. Kulski, Tadaaki Moritomo, Takashi Shiina

The dog leukocyte antigen (DLA) class I genomic region is located on chromosome 12, and the class I genomic region is
composed of at least two distinct haplotypic gene structures, DLA-88–DLA-12 and DLA-88–DLA-88L. However, detailed
information of the genomic differences among DLA-88, DLA-12, and DLA-88L are still lacking at the full-length gene
level, and therefore, DLA allelic sequences classified for each of these loci are limited in number so far. In this study, we
determined the DNA sequence of a 95-kb DLA class I genomic region including DLA-88, DLA-12/88L, and DLA-64 with
three DLA homozygous dogs and of 37 full-length allelic gene sequences for DLA-88 and DLA-12/88L loci in 26 DLA class
I homozygous dogs. Nucleotide diversity profiles of the 95-kb regions and sequence identity scores of the allelic sequences
suggested that DLA-88L is a hybrid gene generated by interlocus and/or intralocus gene conversion between DLA-88 and
DLA-12. The putative minimum conversion tract was estimated to be at least an 850-bp segment in length located from the
5ÅLflanking untranslated region to the end of intron 2. In addition, at least one DLA-12 allele (DLA-12*004:01) was newly
generated by interlocus gene conversion. In conclusion, the analysis for the occurrence of gene conversion within the dog
DLA class I region revealed intralocus gene conversion tracts in 17 of 27 DLA-88 alleles and two of 10 DLA-12 alleles, suggesting
that intralocus gene conversion has played an important role in expanding DLA allelic variations.

Immunogenetics

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