Evidence of novel transposable element excisions from the b4 allele of albino zebrafish

Two of the most important genes underlying the light skin color of Europeans are SLC24A5 and SLC45A2 . The zebrafish orthologue of SLC24A5 is the golden gene. Sequencing of several albino alleles in zebrafish revealed mutations in slc45a2 . We found that the embryonic albino mutant phenotype was rescued by injection of wild type slc45a2 mRNA and phenocopied in wild‐type embryos by a morpholino targeted to the translation start site of slc45a2 . The alb KK allele contains the point mutation GGA(Gly461)>TGA(stop), and the original alb b4 allele contains an ~4 kb insertion. In two lines traceable to b4 , the insertion appears to have been imperfectly excised, leading to 2 or 6 nucleotide deletions (the latter associated with a 2 aa deletion). We think that the insertion sequence is a novel transposable element because it has terminal inverted repeats, target site duplication is associated with the insertion, a blast search of the insertion sequence is present in multiple copies in the ZV9 zebrafish reference genome and the sequence of the insertion does not match that of any known transposable element. NIH funding: 5R01 AR052535 ‐02