Transcript Corn Snakes

Corn Snakes Elaphe guttata
Different phenotypes and genotypes of one species
Pictures thanks to serpentine widget
Why do snakes look different when they
are the same species ?
 Corn snake color is comprised of two predominant colors
 Red
 Black
 Yellow, appears in varying degrees and is not the main reason
for pattern change
 Phenotypes of corn snakes include
 Normal –red and black occur together
 Amelanistic – only red
 Anerythristic- only black
 Snow- neither
Genotype and Phenotype
 Two genes that code for color
 Gene for black color on the ventral surface (belly) and around
the saddle patterns
 Gene for red color in the pattern of the saddles and the back
ground on the snake
 Wild type allele B- black pigment
 Recessive b- can no longer make black pigment- amelanistic
 Wild type allele R- red pigment
 Recessive r- can no longer make red pigment- anerythristic
 Double recessive- Snow Corn Snake (rrbb)
Cross each one of Mr. Reed’s Snakes
 Mr. Reed has these snakes
 amelanistic corn snake (RRbb or Rrbb),
 a normal corn snake (RRBB or RrBb),
 a snow corn snake (rrbb)
 Could Mr. Reed breed his snakes to make an Anerythristic
snake (no red pigment)?
 What is the genotype for the Anerythristic snake?
 Which parental genotypes could you cross to create an
Anerythristic snake? List all possible crosses.