New research published in PNAS examined how a single genetic switch controls mimicry in the swallowtail Papilio alphenor. Growing wings normally involves many genes, but the researchers found that variation at one location can change wing colour patterns between forms.
The study focused on a so-called supergene called doublesex. Unlike many supergenes, doublesex acts alone in these swallowtails to control female mimicry. The team used modern genomic sequencing and experimental tools including CRISPR to test how doublesex evolved and functions.
They found the new allele had few differences in protein structure but had gained six cis-regulatory elements nearby. These elements, working with the doublesex protein, change how the gene is turned on to produce the mimetic female pattern. The allele also regulated several downstream genes involved in body plan development and wing patterning. The work was led by Nicholas VanKuren at the University of Chicago and supported by the National Institutes of Health.
Difficult words
- mimicry — when one species looks like another species
- allele — one version of a gene at a location
- cis-regulatory element — short DNA sequence that controls gene activitycis-regulatory elements
- supergene — group of linked genes acting together
- genomic sequencing — reading the DNA order across a genome
- downstream — acting later in a biological process
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Discussion questions
- Why is it important to know that one gene can control mimicry in butterflies?
- What are possible benefits or risks of using tools like CRISPR to study or change genes in animals?
- Can you think of other animals where mimicry or camouflage is useful? Give an example and explain.
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