The Hairless Phenotype of the Hirosaki Hairless Rat Is Due to the Deletion of an 80-Kb Genomic DNA Containing Five Basic Keratin Genes

April 2008 in “ Journal of Biological Chemistry ”

Naoki Nanashima, Miki Akita, Toshiyuki Yamada, Takeshi Shimizu, Hajime Nakano, Fan Yang, Shigeki Tsuchida

keratin genes hair follicle hypotrichosis chromosome 7q36 non-allelic homologous recombination

TLDR Hirosaki hairless rats lack hair due to missing DNA with key keratin genes.

The study found that the hairless phenotype in Hirosaki hairless rats (HHR) was due to the deletion of an 80-kb genomic DNA segment on chromosome 7q36, which included five basic keratin genes. This deletion, caused by non-allelic homologous recombination, led to the absence of crucial keratin proteins necessary for hair growth, resulting in defective hair follicle formation. The research highlighted the importance of these keratin genes in hair growth and provided the first report of hypotrichosis due to their deletion, suggesting that similar genetic mechanisms could be explored in humans using rodent models.

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