HSC 4555 Lecture Notes - Tyrp1, Melanocortin 1 Receptor, Oca2
Document Summary
_two genes are involved in the coloration of labradors. _the first is a gene for a protein called tyrp1, which is found in pigment storing organelles. _we will denote nonfunctioning allel e as b . A heterozygous (bb) or a homozygous dominant (bb) individual will be black coated while a homozygous recessive (bb) individual will be brown. _the second gene is tied to the gene for melanocortin 1 receptor (mc1r) and influences if the dark pigment is expressed in the fur. This gene has the alleles denoted e or e . A yellow labrador will have a genotype of either bbee or bbee. _the ee alleles prevent the expression of the b alleles and thus prevent expression of the chocolate / brown or black colors. _there are more genes we don"t know about. That can be seen by various circumstances of inheritance. _currently, over 150 genes have been found that influence eye, skin and hair color.
