Few Simple Sequence Repeats in Human Hair

Abstract

Abstract:Keratin genes are subgroup of intermediate filament (IF) genes. Keratins expressed in hair are called "hair keratins". Comparison of keratin gene sequences and structural organization has been done earlier but no study has been undertaken that compares human hair keratin genes with orthologues in chimp, orangutan, macaque and platypus, with specific references to simple sequence repeats (SSRs) or microsatellites. This study seeks presence of SSRs in human hair keratin genes and compares their positions in orthologue genes. Although the structural organization of keratin genes is largely conserved, as reported in other studies; some human keratin genes show differences in the number of exons and the lengths of exons/introns, when compared with the orthologues. The present study shows few SSRs in human hair keratin genes, where only one repeat is found in exon of Type I keratin gene KRT31, while additional repeats are present in introns. Some repeats are longer in the human genes whereas some indicate reduction in length compared with orthologues. Many repeats are present in regions that are known for intronic variations. This study revisits the comparisons of structural organization of human hair keratin genes and compares them with the orthologues. The SSRs found here could be useful for monitoring variations in human hair keratin genes that may happen due to hypermutable nature of SSRs.