Melbourne, Feb 15 (PTI): A father's diet can affect the son's ability to reproduce, according to a new study that debunks the belief that males just pass on genetic material and not much else to their offspring.

The study sought to understand if the nutritional history of fathers had an effect on their sons. Experiments were carried out in the fruit fly, which shares many similar pathways and characteristics with human genes.

The study highlighted the importance of the paternal environment on future generations, even a long time before offspring were produced, said Susanne Zajitschek from Monash University in Australia.

"Our study found that males that were raised on either high or low protein diets, but spent their adulthood on an intermediate diet, produced sons that had large differences in gene expression, which most likely contributed to the resulting differences in sperm competitiveness," said Zajitschek.

"They differed in their ability to sire offspring, with the high-protein dads producing sons who were doing much better in sperm competition, which means their sperm was more likely to win against a competitor's sperm within the female tract," she said.

"We also found that the immune response genes were less active in sons of low-protein fathers, while metabolic and reproductive processes were increased in sons of fathers on a high protein diet," she added.

The research is one of only a few studies to have so far reported trans-generational effects in relation to diet quality, and one of the first to report on the post-copulatory advantages conferred by parental diet.

Researchers examined how high- and low-protein paternal larval diet influenced post-copulatory sexual selection and gene expression in the sons of fruit flies (Drosophila melanogaster). The study was published in the journal Biology Letters.