Genetic variation within ABCE1 is associated with the chicken L blood system

Chicken nucleated red blood cells have thirteen alloantigen systems (A, B, C, D, E, H, I, J, K, L, N, P, R) that have been identified using specific alloantisera and molecular analyses. Until recently, the only alloantigen with its genetic region identified was the B system which is the chicken MHC. This study sought to identify the chromosomal location and the gene encoding chicken L alloantigen. Multiple unrelated genetic resources for which both DNA and serologically defined L alloantigen information were utilized including segregating pedigreed samples, elite commercially utilized egg production lines with known L system serological information, and genome sequence from selected research lines with known L system alleles. Genomic information was obtained from 600 K or 54 K SNP arrays, or low pass sequence information and utilized in GWAS to identify a candidate region. A strong GWAS peak was identified on chromosome 4 between 29.8 and 32 Mbp from multiple sample sets. The candidate gene identified was ABCE1, whose mammalian gene product is non-membrane bound. The specific mechanism by which the ABCE1 gene product in chickens impacts a serological determinant detected by hemagglutination remains unknown.