April 12, 2024

This is why roller pigeons do backflips


Atoosa Samani started learning about pigeon genetics at a young age. She grew up surrounded by pet pigeons in Isfahan, a city in central Iran famous for its pigeon towers. Her favorite was an all-white bird. But 6- or 7-year-old Samani noticed that this particular pigeon never produced completely white offspring.

She discovered that white color is a recessive genetic trait – a trait that is only visible when an individual inherits two defective copies of a gene (SN: 2/7/22). In this case, the pigeon had two broken copies of a gene that normally produces pigment to color feathers, so its feathers were white. But his offspring inherited a normal, pigment-producing version of the gene from their mothers and had colored feathers.

That early lesson in pigeon heredity stuck with Samani and fueled her desire to learn more about genetics. When she moved to the United States to study at the University of Utah in Salt Lake City, it seemed only natural to join Michael Shapiro’s lab to investigate why some pigeons (Columba livia) doing backflips (SN: 1/31/13).

These roller pigeons come in two varieties: flying rollers such as Birmingham rollers, which fly but make long tumbling runs to the ground before resuming flight, and parlor rollers, which cannot fly but instead flutter backwards along the ground. Many Persian poems say that the pigeons perform the acrobatics because the birds are happy, but Samani says the truth is darker. “This is definitely a movement disorder, and there are no good aspects to it,” she says. The condition is progressive, appearing soon after hatching and gradually worsening until the birds can no longer fly.

Samani focuses on the genes behind backflips. At least five genes are involved in the behavior, she reported March 7 at the Allied Genetics Conference in National Harbor, Maryland.

In addition to studying pigeon genetics, Atoosa Samani, pictured here with a Wilson’s Warbler, also volunteers with a bird banding group and enjoys birdwatching. “I love birds,” she says. But she admits that pigeons are her favorites.Thanks to A. Samani

Her colleagues confirmed that backflipping is a recessive trait by breeding homing pigeons with parlor rolls; none of the hybrid offspring rolled. When hybrid birds were bred together, about four in 10 offspring somersaulted when forced to fly, Samani said at the conference.

Samani used two different statistical methods to locate genes that cause the pigeons to tilt the tail feather over the kettle. She found five large pieces of DNA containing hundreds of genes. But none of the genes in those areas had mutations that could explain the tumbling.

So she looked at gene activity in the birds’ brains and found nearly 2,000 genes that become more or less active in the brains of parlor birds than in two breeds of non-rolling pigeons.

Combining all lines of evidence, Samani narrowed her search to about 300 genes that could lead to roles but could not yet link cause to a specific gene.

Samani will soon complete her Ph.D. and hopefully move on to a career in teaching. She will miss the pigeons and the mental exercise they gave her, she says. “I’ve been thinking about this for five years. I have a piece of the puzzle here. I have a puzzle piece there. How can I put them together so they make sense? … Do they actually fit together? … That’s what I’ll miss the most,” she says. “I like solving mysteries.”

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