They tell us this can only happen to flies:
Scientists have discovered a new form of non-genetic inheritance, showing for the first time that offspring can resemble a mother’s previous sexual partner — in flies at least.
This confronting idea, known as telegony, dates back to ancient Greek times, but was discredited in the early 20th Century with the advent of genetics.
To test it out, UNSW Australia scientists Dr Angela Crean, Professor Russell Bonduriansky and Dr Anna Kopps manipulated the size of male flies and studied their offspring.
They found that the size of the young was determined by the size of the first male the mother mated with, rather than the second male that sired the offspring.
“Our discovery complicates our entire view of how variation is transmitted across generations, but also opens up exciting new possibilities and avenues of research. Just as we think we have things figured out, nature throws us a curve ball and shows us how much we still have to learn,” says lead author Dr Crean.
The researchers propose that the effect is due to molecules in the seminal fluid of the first mate being absorbed by the female’s immature eggs and then influencing the growth of offspring of a subsequent mate.
Newly discovered non-genetic mechanisms break the link between genes and inheritance, thereby also raising the possibility that previous mating partners could influence traits in offspring sired by subsequent males that mate with the same female (‘telegony’). In the fly Telostylinus angusticollis, males transmit their environmentally acquired condition via paternal effects on offspring body size. We manipulated male condition, and mated females to two males in high or low condition in a fully crossed design. Although the second male sired a large majority of offspring, offspring body size was influenced by the condition of the first male. This effect was not observed when females were exposed to the first male without mating, implicating semen-mediated effects rather than female differential allocation based on pre-mating assessment of male quality. Our results reveal a novel type of transgenerational effect with potential implications for the evolution of reproductive strategies. (You have to pay to read the article.)
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