▁as ▁ch ond ro cy tes , ▁cells ▁of ▁the ▁end ocr ine ▁system , ▁and ▁mel an ocy tes . ▁This ▁strip ▁of ▁t issue ▁is ▁found ▁along ▁the ▁d ors al ▁mid line ▁of ▁the ▁emb ry o , ▁and ▁multip ot ent ▁cells ▁migr ate ▁down ▁along ▁the ▁sides ▁of ▁the ▁emb ry o , ▁or ▁through ▁germ ▁layers , ▁to ▁their ▁ult imate ▁destin ations . ▁Mel an ocy te ▁stem ▁cells ▁are ▁called ▁mel an ob last s . ▁Cond itions ▁associated ▁with ▁ab normal ities ▁in ▁the ▁migration ▁of ▁mel an ob last s ▁are ▁known ▁collect ively ▁as ▁pie b ald ism . ▁P ig ment ▁cells ▁of ▁the ▁ir is ▁p ig ment ▁ep ith el ium ▁have ▁a ▁separate ▁emb ry ological ▁origin . ▁P ieb ald ism ▁and ▁am el an ism ▁are ▁distinct ▁conditions . ▁ ▁In ▁m amm als ▁The ▁only ▁p ig ments ▁that ▁m amm als ▁produce ▁are ▁mel an ins . ▁For ▁a ▁m amm al ▁to ▁be ▁unable ▁to ▁chem ically ▁manufact ure ▁mel an in ▁rend ers ▁it ▁completely ▁p ig ment less . ▁This ▁condition ▁is ▁more ▁commonly ▁called ▁al bin ism . ▁Am el an istic ▁m amm als ▁have ▁white ▁hair , ▁p ink ▁skin , ▁and ▁eyes ▁that ▁have ▁a ▁p ink , ▁red , ▁or ▁vio let ▁appearance . ▁Red d ish ▁eyes ▁are ▁due ▁to ▁the ▁lack ▁of ▁p ig ment ▁in ▁the ▁ir is ▁p ig ment ▁ep ith