A blue peafowl in Tamil Nadu. Credit: K Hari Krishnan, CC-BY-SA-4.0

Comparative analyses of blue and green peafowls’ genomes reveal a striking contrast in the number of genes. The blue peafowl has a greater number of coding genes than the green peafowl1.

These additional genes have given the blue peafowl evolutionary and survival advantages over the green peafowl, which is an endangered bird, says a research team at the Indian Institute of Science Education and Research Bhopal in Madhya Pradesh.

The scientists, led by Vineet Kumar Sharma, compared the genomes of the two peafowls with those of 49 other bird species. They found that genes related to neuronal development, immunity, and skeletal muscle development evolved significantly in these peafowl species.

The blue peafowl has a higher number of species-specific gene clusters, duplicated genes, and expanded gene families, plus comparatively higher evolution in its neuronal and developmental pathways.

The researchers identified 4,119 genes in blue peafowls and 3,960 genes in green peafowls with increases in the number of exons. These are parts of genes that contain information for making proteins.

In both species, exons in 16 genes expanded at least 10 times. Among them is titin, which encodes a force-generating muscle protein that has a role in flight. This gene exhibited the highest number of exon expansions in the blue peafowl.

Disturbance by humans and habitat loss has forced green peafowls to adapt to environments different from those of blue peafowls. This has caused some green peafowl genes to lose their functions, leading to their deletion, the researchers say.