Comparative genomics of the keratin-associated protein (KAP) gene clusters in human, chimpanzee, and baboon

Abstract

We have previously identified a cluster of 16 genes that encode hair-specific proteins, called keratin-associated proteins (KAPs), located on human Chromosome (Chr) 21q22.3. Here, we have identified similar KAP gene clusters in two primates, chimpanzee and baboon. DNA sequence comparison revealed the common cluster structure consisting of 16 KAP genes for these three primates, but a significant difference was found in the baboon. Baboon possesses a new KAP gene not found in human and chimpanzee, whereas one KAP gene ( KRTAP18.12) that exists in human and chimpanzee was lost in baboon, making no change in the total number of KAP genes. Interestingly, the sequence for coding regions are highly variable among species owing to insertions and deletions, resulting in variation of gene size. On the contrary, the sequences for the 5' upstream region are highly conserved among species. These findings suggest that the ancestral KAP gene cluster was composed of 17 genes before the divergence of Old World monkeys (baboon) to the anthropoid (human and chimpanzee).

Mammalian keratin associated proteins (KRTAPs) subgenomes: disentangling hair diversity and adaptation to terrestrial and aquatic environments

“…Some KRTAP genes appear to possess small introns. However these are similar to repeat regions present in the gene [ 98 ] and can be translated in-frame with the coding exon, leading to the conclusion that all KRTAP are intron-less [ 14 , 99 ]. The presence of KRTAP gene clusters in mammalian genomes makes it easy to identify and fully characterize the gene family in genomes with high coverage, but in low coverage genomes it requires much more manual inspection and in-depth screening to insure an almost complete or maximum possible repertoire of non-redundant KRTAP genes (Additional file 2 ).…”

Highly Conserved Keratin-Associated Protein 7-1 Gene in Yak, Taurine and Zebu Cattle

“…Currently, more than 100 KRTAP genes with high sequence homology within each family have been identified from around 30 KRTAP families. These gene families are found to present in clusters in several genomic regions of the mammalian genome (McLaren et al, 1997;Shibuya et al, 2004;Rogers and Schweizer, 2005;Shimomura and Ito, 2005;Parry et al, 2006;Barthélemy et al, 2012;Gong et al, 2012a;Matsunaga et al, 2013). It was Vol.…”