Scientists from different research organizations in the United States have discovered a particular gene in fruit flies that may cause the insects to give birth to infertile or even dead offspring.

The new finding provides researchers with more information on molecular and genetic processes responsible for the development of new species.

In a study featured in the journal Science, University of Utah researcher Nitin Phadnis and his colleagues from the University of Washington and the Fred Hutchinson Cancer Research Center identified a component in organisms known as the "hybrid inviability" gene that is linked to the ability of species to successfully breed with others.

Phadnis explained that in order to understand how speciation works, one has to identify how reproductive barriers that prevent mating between species develop.

He said that determining such genes and unlocking the molecular basis behind death or hybrid sterility are crucial to understanding the evolution of new species. These aspects have remained largely unanswered since Charles Darwin's time.

Hybrid Inviable Gene

According to the researchers, the hybrid inviable gene in fruit flies, known as gfzf, is considered to be a cell cycle-checkpoint gene or a cell cycle-regulation gene. This type of gene is responsible for helping stop cells from dividing or replicating if the body detects potential defects.

When the gfzf gene was disabled or mutated during the study, it allowed male hybrids from two species of fruit flies (Drosophila simulans and Drosophila melanogaster) to survive.

Phadnis and his colleagues observed that the gfzf gene is capable of evolving rapidly, a trait that is common in those responsible for hybrid inviability.

What the researchers found surprising, however, is that as a cell cycle-checkpoint gene, the gfzf also evolves slowly. This is because they are considered to be "conserved" genes as well, which makes them important to most organisms.

Phadnis said that this trait of the gfzf and its ability to trigger death or infertility in hybrids of fruit flies is what makes the gene essential to cancer biology research.

"Cancer biologists are interested in cell cycle checkpoints because you can get cancer when those go bad [and cells proliferate uncontrolled]," Phadnis pointed out.

"Biologists want to understand the machinery. This work shows that some of those components in the cell cycle policing machinery may be quickly changing."

The researchers encountered several technical difficulties in determining the gfzf as the gene responsible for speciation. Phadnis said he believes that making use of similar methods could help explain the importance of speciation in other species.

Photo: John Tann | Flickr