Inheritance of the Green Vertebral Stripe in Acris crepitans

Abstract

The phenotype ratio obtained from crosses between green-striped cricket frogs (Acris crepitans) shows that the presence or absence of the green vertebral stripe is determined by a pair of alleles in which the gene for green stripe is dominant. Certain individuals of the cricket frog, Acris crepitans, have a green vertebral stripe, while others lack the green stripe color. If the vertebral stripe is not green, it is often some shade of gray similar to other light parts of the dorsum, or it may be any of several shades of red, brown or reddish-brown. The objective of the work presented herein was to learn the method of inheritance of the green vertebral stripe. All frogs that did not have a green stripe will be referred to as Evidence was presented in an earlier paper indicating that the presence or absence of the green stripe is determined by a single pair of alleles with dominance (Pyburn, 1961). Data from green x nongreen and nongreen x nongreen crosses fitted a green dominant- nongreen recessive hypothesis with the exception that one non- green x nongreen cross produced both phenotypes in about equal num- bers. Since under certain circumstances a frog with a green stripe at metamorphosis may appear gray later on, it was suggested that one of the parents in the one dissenting cross had lost the green color and was therefore recorded as nongreen. An alternative explanation is that no such loss of color had occurred, and that nongreen is dominant to the green-striped condition. If so, a cross between any two green- striped frogs could produce only green-striped offspring. If, on the other hand, green is dominant and nongreen recessive, crosses be- tween green-striped frogs would be expected to yield either all green offspring, or both phenotypes in the ratio 3 green : 1 nongreen. Until recently all green x green crosses had failed to produce metamor- phosed offspring under laboratory conditions. Young frogs have now been obtained from two green x green matings, which form the basis of this report.