Genomic orientation of β-keratins in birds. This figure is a genomic alignment of β-keratins in birds containing a genomic locus with at least two β-keratin subfamilies. For the chicken and zebra finch this locus is microchromosome 25. Although feather β-keratins can be found on many genomic loci other than the one shown here , we focused on this locus as it has members from all of the β-keratin clades. The annotations are based on our β-keratin phylogeny (Additional file 4; ). The breaks in the line for each species are indicative of different genomic scaffolds. The direction of the arrow is indicative of the DNA strand. The arrows with solid colors are complete genes and those with white centers are incomplete genes. The annotation above the figure is based on each of the four β-keratin subfamilies, while the clades based on the β-keratin phylogeny (Additional file 4; ) are shown below the figure.