TLDR The study found that variations in hair protein genes are likely due to evolutionary deletions or duplications.
The study focused on the human ultrahigh sulfur keratin-associated protein 4 (KAP4) genes, which are crucial for hair fiber structure and are located on chromosome 17q12-21. Previously, a gap in the sequence made it difficult to fully characterize these genes, but the gap was bridged by the human bacterial artificial chromosome clone AC100808. The researchers analyzed the nucleotide sequences from AC100808 and used PCR amplification to identify numerous size polymorphisms in the KAP4 genes. These polymorphisms were primarily due to variations in the sequences that encode cysteine-rich repeat segments. The findings suggest that these polymorphic alleles of the KAP4 genes may have developed through the deletion and/or duplication of sequences encoding the repeat structures during the course of evolution.
62 citations,
January 2004 in “The journal of investigative dermatology/Journal of investigative dermatology” A second domain of high sulfur KAP genes on chromosome 21q23 is crucial for hair structure.
17 citations,
June 2003 in “The journal of investigative dermatology. Symposium proceedings/The Journal of investigative dermatology symposium proceedings” Mutations in hKAP1 genes may cause hereditary hair disorders.
100 citations,
December 2002 in “Journal of biological chemistry/The Journal of biological chemistry” Researchers mapped and categorized specific keratin-associated protein genes on human chromosome 21q22.1.
48 citations,
November 2002 in “Journal of biological chemistry/The Journal of biological chemistry” Genetic variations in hair keratin proteins exist but don't significantly affect hair structure.
24 citations,
February 2002 in “The journal of investigative dermatology/Journal of investigative dermatology” Two new proteins, hKAP1.6 and hKAP1.7, are found in the hair follicle cortex.
98 citations,
June 2001 in “Journal of biological chemistry/The Journal of biological chemistry” A cluster of sulfur-rich hair protein genes was found on chromosome 17.
48 citations,
July 1993 in “The journal of investigative dermatology/Journal of investigative dermatology” Hair growth is controlled by specific gene clusters and proteins, and cysteine affects hair gene expression in sheep.
27 citations,
June 2005 in “The journal of investigative dermatology/Journal of investigative dermatology” The study found that variations in hair protein genes are likely due to evolutionary deletions or duplications.