Young/Old Cells, What Changes?

[Robert Luly]

Bob Walsh (walshb at beep.roadrunner.com) wrote:
: Bob Walsh (walshb at beep.roadrunner.com) wrote:
: : ... do the follicle cells for a grey hair have the
: : same DNA as the follicle cells for a normally pigmented hair taken
: : from the same individual on the same day?

: Following up on my own question:
: "Hair pigment is made by melanocytes at the base of the hair follicle
: ....  Gray or white hair results from a decrease in melanin production
: (mediated by delayed-action genes) and the replacement of melanin by
: air bubbles in the hair shaft."  Elaine N. Marieb, Human Anatomy and
: Physiology, 1992.  No futher discussion or references given there
: on "delayed-action genes."

: Bob Walsh (walshb at alumni.caltech.edu)
: Santa Fe, NM, USA (505) 263-1875
: FAX:  (505) 983-5868

Even if cell types are made with the same genes, maybe all cells don't 
progress at the same rate.??