Survival rates of follicles and follicular units were once thought of only being influenced by where the grafts were transplanted to and not just a mere factor of how they were extracted. In 1959 a physician Orentreich coined the term donor dominance. Donor dominance was the influence of the area of the transplanted grafts and where they came from. If the grafts came from a hair bearing area, then the characteristics of the grafts would be retained and the balding areas had no affect on the grafts. In other words the grafts would maintain the same color, texture, and growth rates would be the same including the same length of anagen phase. At some point in hair restoration, there were thoughts that the recipient area played a larger influence on the transplanted grafts whereby the characteristics of the grafts would conform to the area of transplantation. This was proved wrong over the years by several studies. Dr. Tommy Hwang carried out several types of studies such as transplanting scalp hair into varies areas of the body. The only differences Hwang found was that the survival rates were decreased and the growth rates were slower. This was hypothesized to be from several varied factors such as a different blood supply, different thicknesses in the dermis, epidermis, subcutaneous tissues, and hormonal factors as well as the fact that the slowed growth rate was immediate proving the recipient area had no influence. All other characteristics remained the same.
Some interesting facts are that the human scalp’s anagen phase is between 2 and 6 years. Also it was postulated that the closer the transplanted hair were to the scalp such as transplanting scalp hairs on the face neck and back, the survival rates and growth rated would increase to that of the scalp. This proved to be correct over a long period of time.
in conclusion the growth rates and survival rates are affected by the recipient area however not for genetic reasons of that being in the area of the recipient but moreover by the anatomical features influencing the grafts.