Fig. 1

a Schematic overview of BTA20. Yellow shaded parts mark the candidate haplotype, an orange line indicates the position of SLC45A2 [chromosome adapted to the illustration on CattleQTLdb (http://www.animalgenome.org)]. b Schematic overview of the SLC45A2 gene sequence. Blue arrows indicate the orientation of transcription of SLC45A2. Red lines mark the positions of the two candidate mutations. Exact position according to UMD 3.1, modification and SIFT score are given for each SNP. c Excerpt of the multi-species alignment performed by HomoloGene that clearly shows that p.R45Q is conserved in contrast to p.T444I (indicated in bold face)