Many anurans, such as frogs and toads, have a light-colored stripe on their backs that, when viewed from above, creates the optical illusion that they are split in half, which can interfere with predators that rely on visual hunting.
Although this stripe is widespread in anurans, little is known about its evolutionary and genetic origins.
In a recent study published in Molecular Biology and Evolution, scientists compared the dorsal stripes of more than 2,700 anurans and found that the stripes have evolved hundreds of times and appear more frequently in terrestrial anurans.
In studying a grass frog (Ptychadena robeensis) with a polymorphic dorsal stripe, scientists found that the expression levels of genes regulating Agouti signaling proteins (ASIP genes) correlated with the stripe morphology of the species, with grass frogs showing wide stripes at higher gene expression levels and thin stripes at lower levels.
They further speculate that this rapid evolution of dorsal stripes may make anurans more adaptable to environmental changes or other alterations.
This study is the first large-scale study of vertebrate stripes in anurans and establishes the first link between ASIP genes and color patterns, opening up new avenues of research for future comparative studies of anuran and vertebrate color patterns.