ANTHR 102 Lecture Notes - Lecture 16: Human Skin Color, Epistasis
Document Summary
Pleiotropy single gene may contribute to production of more than one phenotypic feature. Or changes in a gene (mutations) may have more than one phenotypic expression. Polygeny many genes regularly combine forces to produce a single morphological/phenotypic feature. Or a particular phenotypic feature may be the product of multiple genes. Most cells have more than one gene most are polygenic. Classic example = a few major genes + additional minor genes + environmental input. Lost hair became more exposed to sun. Favored tan easily in summer; lose tan in winter. Clines: gradations along a continuum; gradual, not abrupt genetic shifts. When we compare two things, the categories are relative to each other dark/light, big/small, curly/straight. If someone of my height stands next to someone of 6"2 , then i am labeled. Short and they are labeled tall add someone who is 5" or 6"5 to the mix and our labels change.
