Can a Baby Look like the Mother’s Ex?

The offspring of fruit flies exhibit such a phenomenon

A favourite pastime among new parents is the discussion over which of their baby’s various facial features resemble theirs and those of other close relatives. But is it possible that the baby could also exhibit the physical traits of his mother’s previous sexual partner?

The concept of telegony, where a child inherits the traits of the mother’s pervious mate, has in the past been hypothesised by scholars like Aristotle. But with scientific advancement, this theory had been junked. Yet, now a new study, conducted on fruit flies, proves that such a scenario is not implausible.

The study, published in Ecology Letters, was conducted by researchers from University of New South Wales. They carried out a series of mating experiments with female flies when their eggs were immature. They mated the immature females with either a large or small male. And once the females had matured, they were mated again with either a big or small male. Those originally mated with a larger male continued to produce larger offspring even when mated with a small male. Genetically, the young flies were the offspring of the second, smaller male, but physically, they resembled the larger male. When the experiments were repeated with a group of male flies whose genitalia were glued down so they could not pass on any semen during their sexual encounters, their size did not have an effect on the offspring of the female with her second mate. According to the researchers, the offspring was taking the physical traits of the mother’s previous mate because the molecules in the semen of the first mate were being absorbed by the female’s immature eggs, thus influencing future offspring.

The researchers write in the journal, ‘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’)… Our results reveal a novel type of transgenerational effect with potential implications for the evolution of reproductive strategies.’ While there is no scientific evidence that something like this can occur in human beings, the researchers do not rule out the possibility.

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