Imagine stumbling upon a creature that looks like it wandered out of a sci-fi novel, with fur that’s pitch black or eerily luminous yellow—now picture this as perfectly normal for its species. That’s the fascinating reality for some of Australia’s most elusive marsupials, where ‘broken’ genes aren’t flaws but key players in their vibrant (or shadowy) appearances. But here’s where it gets controversial: what if these genetic glitches are actually giving these animals an evolutionary edge, challenging our ideas about what makes a trait ‘normal’ in the animal kingdom?
A groundbreaking study from La Trobe University has uncovered that the striking fur colors of two of Australia’s rarest marsupials—think the mysterious desert-dwelling marsupial mole and the black-coated version of the endangered eastern quoll—might stem from these very ‘broken’ pigment genes. These animals are part of a growing list of marsupials displaying unusual color variations, often called morphs, which can include extremes like melanism (that deep, dark black coating) or xanthism (a bright, yellowish hue).
In many animals, such color oddities are seen as chromatic disorders—essentially genetic hiccups that could make survival tougher by making them stand out to predators or affecting their camouflage. Yet, this research, published in the journal Biology Letters (link: https://royalsocietypublishing.org/doi/10.1098/rsbl.2025.0302), reveals a surprising twist: for an increasing number of marsupials, these color variants aren’t rare anomalies; they’re widespread or even the default look for the entire species. And this is the part most people miss: it suggests that in some cases, what we call a ‘broken’ gene might actually be an advantageous adaptation.
Let’s break it down for clarity, especially for those new to genetics. In the case of the black morph eastern quolls, scientists found a chunk of DNA missing that disables the Agouti Signaling Protein (ASIP) gene. Normally, this gene helps produce pheomelanin, a pigment that gives fur light yellow-to-red tones. Without it functioning properly, the animals end up with more of the darker pigment, eumelanin, leading to those striking black coats. Intriguingly, a very similar DNA deletion has been spotted in the Tasmanian devil, a close relative of quolls with its own blackish-brown fur. By analyzing the sequences around these deletions, researchers confirmed that both quolls and devils evolved this trait separately—a classic example of convergent evolution (link: https://phys.org/tags/convergent+evolution/), where unrelated species develop similar features in response to similar pressures, like environmental needs.
Meanwhile, the team turned their attention to the enigmatic marsupial mole, a ‘sand-swimming’ critter that calls Australia’s harshest deserts home, thanks to a newly available genome assembly (link: https://phys.org/news/2025-01-scientists-deepest-evolutionary-secrets-australia.html). Unlike most mammals, marsupial moles sport a xanthic coat—that’s a pale yellow shade—due to a lack of the dark eumelanin pigment. Here, the culprit is a mutation in the Melanocortin 1 Receptor (MC1R) gene, which shortens the protein and stops it from working. To help beginners grasp this, think of ASIP and MC1R as a molecular switch in a lighting system: one controls when to add dark eumelanin, the other balances it with lighter pheomelanin. When the switch malfunctions on either side, you get uniform colors instead of the typical banded hairs that create gray-to-brown coats in most mammals.
Study lead Dr. Charles Feigin explained it simply: ‘Normally, MC1R gets turned off periodically by ASIP, creating those alternating dark and light bands in hairs for a blended look. But if either part of the switch breaks down, you lose that balance and produce just one type of pigment.’ This expands our understanding, showing how even ‘faulty’ genes can lead to diversity—perhaps helping these marsupials blend into specific desert sands or stand out for other reasons we haven’t fully explored.
While the full evolutionary benefits of these coat variations in marsupials are still under investigation, ‘broken genes’ appear to be a major factor. Is this a sign that nature rewards the unconventional, turning potential weaknesses into strengths? Or does it complicate our views on genetic ‘disorders’ in wildlife? What do you think—should we rethink how we label these traits as ‘broken’ when they might be perfectly suited to their environments? Share your thoughts in the comments; I’m curious to hear agreements, disagreements, or even wild theories about what this means for conservation!
For more details, check out the full study: Ryan Sauermann et al., ‘Loss-of-function mutations in ASIP and MC1R are associated with coat colour variation in marsupials,’ Biology Letters (2025). DOI: 10.1098/rsbl.2025.0302 (link: https://dx.doi.org/10.1098/rsbl.2025.0302).
Citation: ‘Broken’ genes may play key role in marsupial fur color oddities (2025, October 28). Retrieved 28 October 2025 from https://phys.org/news/2025-10-broken-genes-play-key-role.html.
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