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Albino cane toads created using gene-editing technology reveal that albino animals face competitive disadvantages going far beyond their vulnerability to predators, according to new research published in .

The study, led by Macquarie University Ph.D. candidate Alexander Funk, is the first to use CRISPR to "knock out" specific genes in cane toads, challenging the long-held belief that albino animals are rare mainly because predators can easily spot and kill them.

The team's experiments compared albino and pigmented siblings in controlled environments without predators, revealing a more complex story than traditional evolutionary theory suggests.

Albino tadpoles were less likely to survive and developed faster when competing with non-albino siblings for food and space. Adult albino toads grew more slowly and had much more difficulty catching prey.

"That surprised us鈥攚e expected to see the intense competition in the adult stage, but we didn't expect to see it come out so clearly in its effects on survival in the tadpole stage," Funk says.

The team tested hunting abilities by dropping live termites in containers under different lighting conditions. The tests revealed the core problem: poor eyesight. Albino toads needed much brighter light to catch prey successfully and missed more targets than their pigmented siblings.

"Other studies have shown that albino animals tend to have reduced visual abilities as the condition is linked to poor stereoscopic vision," says Funk. "We were curious how this poor vision might affect them, because cane toads are visual foragers, especially in their adult stage."

Since toads typically feed at night, albino toads would struggle to compete for resources during crucial developmental stages in nature.

The study's broader significance lies in demonstrating how CRISPR technology can tackle fundamental questions about evolution by creating siblings that differ only in a single trait, such as pigmentation.

"We can now apply this emerging power to manipulate the genetic features of animals, to ask fundamental questions in evolutionary biology," says Professor Rick Shine, evolutionary biologist at Macquarie University who supervised the research.

"By removing just one gene, we can directly compare between siblings; same clutch of eggs, same parents鈥攖he only difference is we've disabled the gene for pigmentation."

"This is the first study I'm aware of that looks at the effect of albinism on competition, rather than on being susceptible to predators," says Funk.

Co-author Dr. Chris Jolly says, "As gene-editing technology becomes cheaper and more accessible and affordable, these molecular tools mean we can test long-standing theories about natural selection and survival. Similar approaches could help resolve other evolutionary puzzles."