Among the Green Frogs in the ponds at susquehannawildlife.net headquarters, a specific recessive allele is present among the population of these native amphibians. On occasions when male and female carriers of this particular recessive allele get together to produce offspring, about one quarter of the progeny will receive a copy of this mutated version of a gene from each parent. The rare recipient of this pair of recessive alleles that happens to survive the process of hatching from its egg and metamorphosing through the tadpole stage to adulthood will reveal the uncommon appearance of an amphibian with the condition resulting from this inheritance—axanthism.
*The incidence of axanthic frogs can increase when a blue parent, which has a pair of the recessive alleles and is therefore said to be homozygous recessive, mates with a typical-looking frog that carries both a dominant and a recessive allele for the axanthism gene and is therefore said to be heterozygous. Approximately 50% of the young from this pairing will express axanthism. By comparison, a pair of frogs that are both heterozygous will produce 25% axanthic young, and a pair of frogs that are both blue (homozygous) will yield 100% axanthic young. A pair of frogs that includes an individual that is herterozygous and a mate that is homozygous dominant for the gene will produce no axanthic frogs, but 50% of the young will be carriers of the recessive allele. A pair of homozygous dominant frogs produces no axanthic young and no carriers of the recessive allele.