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Corn Snakes Elaphe guttata Different phenotypes and genotypes of one species
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.