Transcriptional analysis of equine λ-light chains in the horse breeds Rhenish-German Coldblood and Hanoverian Warmblood.

The present study analyzed equine λ-light chain genes (IGLV and IGLC) transcribed in the horse breeds Rhenish-German Coldblood (RGC) and Hanoverian Warmblood (HW). Primers were generated for the major expressed IGLV subgroup 8. The significant majority of the sequences represented IGLC6/7. In RGC, IGLC1 and IGLC5 were observed in significant higher frequencies than IGLC4. In HW, significant differences were obtained for the transcription of IGLC1 and IGLC5. IGLC4 was not determined in this breed. Five allotypic IGLC1 variants, four allotypic IGLC5 variants, and three allelic as well as two allotypic IGLC6/7 variants were identified. IGLC1b, d, IGLC5c, d, and IGLC6/7a3, b were detected in RGC while IGLC1c and IGLC5b were solely found in HW. Furthermore, 11 out of 144 known IGLV-segments were transcribed of which IGLV15 and IGLV17 were preferred significantly. IGLV25 displayed significant differences in the rearrangement between both breeds. The classified pseudogenes IGLV101ψ and IGLV74ψ were also identified. Rearrangements with IGLC-genes showed significant differences for IGLV15 in both breeds, whereas IGLV25 also revealed significant differences between the breeds. The transcriptional orientation of the functional segments has no influence on the occurrence of the IGLV.