What is the secret behind the beautiful tail of the Peacock that foxed Charles Darwin to modern day scientists for long? What is the role of the mesmerising display of its ornamental plumage in evolution?
Indian scientists have scooped up some interesting answers after a deep dive into the study of the genetic makeup of the national bird.
When the Peafowl gets on its display of feathers in a spectacle to the human eye (glittering train and crest plumage and behavioral traits) but in nature it is actually courting for mates. During this sexual selection the birds look at the feathers which have the eye like spots. The more the eye spots the greater the immunity and hence the higher the chances of attracting the opposite sex for mating and reproduction.
Now, the reason why the Blue Peacock, thrives in India is due to its well-developed assembly of genes. The birds are well evolved giving them strong immunity, better neurons and a robust skeletal muscle strength than their cousin, the Green Peacock which faces a sharp decline in population, say researchers from the Indian Institute of Science Education and Research, Bhopal (IISER Bhopal).
According to Dr Vineet K Sharma, Associate Professor and one of the key researchers of the IISER team: “The green peafowl population appears to be more vulnerable to the consequences of habitat loss and human exploitation for food and commercial use. These activities have had a greater impact on their numbers, as they are less tolerant to human disturbances. The reduction in their population has resulted in decreased gene flow, increased inbreeding, and lower genetic diversity, ultimately raising the risk of extinction for this species.
In 2018, the same Institute had for the first time in the world published the entire genome sequence of the Peacock. It has also sequenced the genomes of the Tiger, jamun, banyan and amla too.
The exciting findings
The Researchers from the MetaBioSys Group of the Bhopal Institute have for the first time constructed a high quality genome assembly to decipher the genetic secrets of India’s national bird.
The existence of intricate ornaments in peacock had perplexed scientists for decades and led to several ecological and population-based studies. In the recent past, genetic studies have added to the quest.
The IISER Bhopal team focused on the Blue Peafowl, also known as the Indian Peacock, native to the Indian subcontinent, and the Green Peafowl, found in Southeast Asia. These two species of birds were chosen because despite being the only two species from the Pavo genus, the Blue Peafowl is classified as a species of “Least Concern,” while the Green Peafowl faces endangerment due to a decline in population size.
They found that genes related to nervous system development, immunity, and skeletal muscle development have undergone adaptive evolution in both bird species. However, the Blue Peafowl has more pronounced adaptive evolution, possessing a higher number of expanded gene families, segmentally duplicated genes, species-specific gene clusters, and genes with evolutionary signatures.
Dr Sharma says: “Our findings highlight the distinct genomic divergence between the two Asian peafowl species and provide valuable genomic clues to explain their contrasting population sizes.”
The studies have brought us one step closer to unravelling the genetic basis for the enigmatic bird’s characteristics. The research not only deepens our appreciation for the peacock’s ornamental allure but also broadens our knowledge of evolutionary biology and the genomic underpinnings of nature’s wonders, he said.
Darwin, Ruskin and Peacock
The ornate features of the peacock’s tail have always fascinated scientists and nature enthusiasts. Charles Darwin expressed bewilderment over the paradoxical grand display of the male peafowl, which made it more vulnerable to predators.
Darwin resolved this puzzle with the theory of sexual selection, suggesting that such ornamental traits play a crucial role in attracting mates and enhancing reproductive success. Despite such understanding, the underlying genetic basis for these spectacular birds has always remained a mystery.
The words of Ruskin Bond, “I do not believe that any peacock envies another peacock his tail, because every peacock is persuaded that his own tail is the finest in the world,” capture the essence of the peacock’s extraordinary allure and our fascination with it, said Vineet Sharma.
The recent findings have been published in the journal Heliyon. The paper has been co-authored by Dr. Vineet Sharma, Associate Professor, Department of Biological Sciences, and his research scholars Abhisek Chakraborty, Samuel Mondal, and Shruti Mahajan.
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