New study on the evolution of butterflies turns out that there’s more in the process than meets the eye as it can explain a lot about evolution of other species as well. The study of the full genome sequences of the 32 butterflies from the Central American rain forest, representing five species from a hybridising Heliconius butterfly , concludes that the evolution of new species might not be as hard as it seems, even when diverging populations remain in contact and continue to produce offspring.

Heliconius butterfy

[Picture:  Heliconius butterfy]

Marcus Kronforst | Credit: Kronforst Lab, University of Chicago
Marcus Kronforst | Credit: Kronforst Lab, University of Chicago

“The Butterflies have produced a beautiful natural experiment for us that lets us address important questions about evolution”, said Marcus Kronforst of the University of Chicago. “As Biologists, we often think of origin of new species as a moment in time when a new species splits from an old one and this type of thinking is reflected in the phylogenies that we draw. In reality, evolution is a long term process that plays out in stages and origin of species is no different”

Phylogeny is the sequence of event associated in the evolution of a species or taxonomic group of organisms, especially lines of descent and relationships among broad groups.

Kronforst and his team analyzed the genomes of recently diverged two closely related butterfly species, Heliconius cydno and H. pachinus and manifested the genetic difference which is important for speciation process and came to the conclusion that the initial divergence between the butterflies populations within the same ecological habitat is limited to small amount of genetic exchange.

Wing color patterns in butterflies also determine the crucialness of the genes. They discovered that the butterfly species differed in only 12 small regions of their genomes and 8 of which are coded for wing patterning and they play a very important role in their mating behavior and outwitting predation, while the other 4 remained unknown.

“These 12 spots appear to only function well in the environment their species occupies, and so are prevented from moving between gene pools, even though other parts of the genomes are swapped back and forth,” Kronforst said.

The analogy of genomes of these two species with closely related but, a slightly more distant “third species” brought to light that that process of genetic divergence speed up after the initial changes and it winded up with hundreds of genomic changes which is more rapid than those earlier process of genomic changes.

Kronforst caught himself involving in the situation of a bit like a ‘tug-of-war’ between natural selection and gene flow.

“It is possible that this type of speciation, in which natural selection pushes populations apart, has been important in the evolution of other organisms. It remains to be seen whether it is a common process though,” Kronforst said.

[Source: Cell Reports;  UCM | Image Source: Heliconius]