An important goal of studying evolution is to identify the genetic changes behind the emergence of a new morphological structure in organisms. According to the official website of the University of Cambridge in the UK, scientists have found through genetic sequencing analysis of various Amazon armyworms that the gene switches that control different stripes and spots on their wings are independent, and different armyworms have these gene switches, like a gene "paintbrush box" that can produce new patterns through cross species mating.

For evolution, interspecific gene exchange is very important, and humans have also undergone such exchanges, which may have helped us survive in high latitude regions. In butterflies, exchanging wing patterns can give different butterflies the same warning signals to resist their predators, a phenomenon also known as mimicry. The pattern on the wings of the sleeve butterfly is commonly a combination of two patterns, with a pair of Dennis red spots on the forewings and radiating red stripes resembling fans on the hindwings.

Researchers sequenced 142 sleeve butterflies from 17 species and compared their DNA data, tracing back nearly 2 million years to study how the two patterned regions on their forewings bind together. They found that although the gene switches of these patterns are adjacent to each other, they can operate independently. Starting from the site of accidental hybridization nearly 2 million years ago, each patterned switch has only evolved once, and all sleeve butterflies have these switches.

Professor Chris Jenkins from the Department of Zoology at the University of Cambridge, who participated in the study, said that different color blocks on butterfly wings are controlled by different gene switches and can be independently turned on or off. And these switches are found in various sleeve butterflies, which can generate new patterns through different combinations. By identifying the relationship between the number of gene switches and patterns, when they evolved, and how they differentiated, it is possible to draw an evolutionary tree of sleeve butterfly species and display their inter species color crossing.

Another researcher, Richard Wobank from the Department of Zoology at the University of Cambridge, said that the key to this evolutionary "brush" is that each gene switch is independent, and the genes controlled by the switch are the same, encoding the same protein each time. Due to their independent switches, they are finer and more powerful, allowing for evolutionary patching without affecting the genetic parts that control the brain and eyes. This modularity means that a small switch can produce a certain pattern on butterfly wings with just one gene, like a gene paintbrush box.