23 December 2015
Bad Hair Day
Deep down, we're all stripy. As we grow in the womb, the cells forming our skin migrate across our developing body in stripe-like tracks called Blaschko's lines. These trails don't normally show up in humans, but they're the source of stripes in animals such as cats. This cow has streaks of hair-free skin rather than coloured fur, due to a fault in a gene called TSR2 – involved in hair growth in many mammals including humans – located on one of her X chromosomes. Because cows have two X chromosomes compared with males (who have an X and a Y), they randomly switch one off in every cell to compensate for the double dosage. Due to this random X-inactivation in skin cells, some of them will have to rely on the faulty copy of TSR2 as they grow and migrate in a developing calf, creating the hairless stripes.
Written by
- Image from work by Leonardo Murgiano and colleagues
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Image originally published under a Creative Commons Licence (BY 4.0)
- Published in PLOS ONE, July 2015
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