A BIRD in the Galapagos Islands, known as a cormorant, lost its ability to fly over time due to genetic changes that mirror bone disease in humans, researchers said.

Researchers hope that further study may one day open the door to treatments for bone disorders in people. These DNA changes transpired over the course of two million years, affecting an iconic bird that caught scientist Charles Darwin’s attention in the 1830s, said the study in the journal Science.

A PELICAN and a Galapagos Islands iguana use a San Cristobal Island rock as a perch 21 January, 2001. Oil from the tanker “Jessica,” which ran aground 16 January and was carrying 900,000 liters (240,000 gallons) of oil, is threatening the island. Ecuadoran Environmental Minister Rodolfo Rendon said the spill has extended over a 1,200 square-km (460 square-mile) area. — AFP

Darwin hypothesized that somehow, evolutionary pressures led the bird to lose its ability to fly, but the details of how it happened remained unknown until now.

The Galapagos cormorant is the only one of 40 cormorant species that cannot fly. The large bird has short wings and is an excellent swimmer that survives by diving for fish. “Darwin, just by looking at these changes, inferred the process of evolution by natural selection,” said senior author Leonid Kruglyak, chair of human genetics at the University of California, Los Angeles (UCLA) David Geffen School of Medicine. “We now have sophisticated genetic tools to reexamine these classic examples and uncover what happened at the molecular level.”

Galapagos cormorants have a different version of a gene called CUX1 than cormorants that can fly, the report said. The gene has previously been linked to shortened wings in chickens.

“We saw a mutation in this gene that we’ve never seen in other animals,” said co-author Alejandro Burga, a researcher at UCLA.

Researchers found that when the same gene changes in humans, it causes bone development disorders called skeletal ciliopathies. “People born with skeletal ciliopathies have shorter limbs, narrowed chests and stunted rib cages — as do the Galapagos cormorants,” said the report.

Such evolutionary changes may come about because not flying allows the bird to enhance another survival skill, like swimming and diving for fish. Or, birds may have evolved to no longer fly because they simply did not need to migrate to escape predators.

“These two scenarios aren’t mutually exclusive,” said Kruglyak. “You can start down the path because of passive loss of flight but then also have positive selection to keep reducing wings.” — AFP

RELATED ARTICLESMORE FROM AUTHOR