Scientists identify gene Linked to variations in beak size among Darwin’s finches

Recently, scientists spotted a gene that has shed light on the variations in the beak size in Darwin’s finches. Darwin’s finches are an example of adaptive capabilities among species, and they made their way on the Galapagos nearly two million years ago. They evolved into 18 distinct species with different sizes, songs, beak shapes and feeding practices. In the 1830s, evolutionary biologist Charles Darwin noticed the birds when he visited the islands while on board the HMS Beagle.

Now, Uppsala University and Princeton University researchers have detected the HMGA2 gene as one that plays a part in beak shape and forces changes in that area of the birds’ anatomy. They demonstrated that even with smaller beak, medium ground finches were able to consume more small seeds, giving a tough competition to higher-size finches, which focus on larger seeds, leaving behind the smaller ones.

The transition in beak morphology might have come following a severe drought in the time span between 2004 and 2005, which led to more competition for food between different finch species. For instance, the analysis done by the study authors Peter and Rosemary Grant from Princeton discovered that the medium ground finch backed off from the beak size of the huge ground finch.

The two scientists who conducted field research in the region for four decades said, “The HMGA2 locus played a critical role in this evolutionary shift and that natural selection acting on this gene during the drought is one of the highest yet recorded in nature”.

They found that during that drought episode, the average beak size of medium ground finches became smaller because of a high death rate in the ones with big beaks, which probably weren’t able to ferociously compete with the bigger species.

A report published in EurekAlert revealed, “In the new study, scientists led by senior author Leif Andersson, a genomics professor at Uppsala, worked with the Grants — who have studied natural selection in Darwin’s finches for more than 40 years — to identify the gene that caused the adaptation of the smaller beak.”

“It was an exceptionally strong natural-selection event,” said Peter Grant, adding that because Daphne Major is in an entirely natural state the occurrence was completely unaffected by humans. “Now we have demonstrated that HMGA2 played a critical role in this evolutionary shift and that the natural selection acting on this gene during the drought is one of the highest yet recorded in nature.”

“A team of researchers has identified a gene involved in shaping the beaks of Darwin’s finches – small, seed-eating songbirds in the Galápagos islands, according to a paper published Thursday in the journal Science. The gene, HMGA2, is still actively molding the famous finches today,” according to a news report published by CS Monitor.

“Those with larger beaks tended to die during this drought,” Dr. Andersson tells The Christian Science Monitor in a phone interview. And because the birds with smaller beaks survived that drought best, “there’s a tendency toward smaller beaks now.”

According to a report in TechTimes by Katrina Pascual, “This transition in beak morphology likely happened after a severe drought from 2004 to 2005, when competition for food intensified among various finch species. Work done by study authors Peter and Rosemary Grant from Princeton, for example, found that the medium ground finch moved away from the beak size of the large ground finch.”

“[T]he HMGA2 locus played a critical role in this evolutionary shift and that natural selection acting on this gene during the drought is one of the highest yet recorded in nature,” said the two scientists who carried out field research in the area for 40 years.

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