Context:

• Scientists have decoded the evolution of the distinctive orange and white patterned clownfish — the coral reef fish species that was featured in the popular animated movie ‘Finding Nemo.’ Coral reef fishes, including clownfish, display a wide variety of colours but it remains unclear how these colours evolved or how they develop throughout a fish’s life.

Species of clownfish:

• Studying two species of clownfish — Amphiprion ocellaris and Amphiprion frenatus — that have three stripes and a single head stripe, respectively, researchers found that shortly after hatching, the larvae of neither species had any stripes. Subsequently, both species acquired stripes on head and trunk at the same time, with A. oscellaris acquiring a third stripe near the tail and A. frenatus losing the trunk stripe before reaching adulthood.
• Every clownfish species gains stripes from front to back after they are born, before individuals of some species lose stripes again from back to front as they grow into adults, which is similar to the loss of stripes observed during clownfish evolution.
• While clownfish species vary in their number of stripes from zero to three, there is limited variation in how these stripes are organised. In all two-striped species, the stripe nearest the tail has been lost, while the head and the trunk stripes are retained. All one-striped species have retained the head stripe and have lost the trunk and tailfin stripes.

Source:TH