Re: non-functional Mc1r makes people have red hair???

Dear Edouard:

The influence of the melanocyte-stimulating hormone receptor (MC1R, MSHR) on hair color is a fascinating example of only a few physical characteristics that have been conclusively linked to a specific gene in humans so far. However, MCR1 is not necessarily completely non-functional in individuals w/ red hair. Their MCR1 genes seem to often carry mutations that disrupt their response to the melanocyte-stimulating hormone so that their melanocytes don't produce enough of the dark pigment, eumelanin. But the varying shades of red hair observed in humans appear to be the result of varying degrees of this disruption caused by different mutations.

With regards to your question about whether or not this characteristic can 'be done on purpose', the short answer is; not @ the present time. BUT the technology for genetic engineering & gene therapy is currently the subject of intensive research w/ some encouraging results. So the future possibilities would undoubtedly be more promising.

However, recent studies indicate that genes other than MC1R also contribute to the human red hair phenotype, as is the case w/ numerous other human genetic traits. So "engineering" red hair would probably not be as straightforward as it might seem, based upon these early findings.

Thanks very much for your excellent question, & I hope that some of these links are helpful,

Jeff Buzby, Ph.D.
CHOC Research Institute
MadSci Genetics Network