Grandchicks of old grandmas are born „old“

As animals age, they generally look less good and their telomeres, small structures that protect chromosomes from becoming frayed or tangled, become shorter. A recently published study co-led by the University of Veterinary Medicine Vienna examined if the effects of age at conception of mothers to the telomeres of their offspring would persist over a subsequent generation (grandoffspring generation).

Foto: pixabay

The offspring of older animals often have a shorter life expectancy. This is associated with a shorter telomere length of the offspring. However, it was not previously known whether such telomere shortening persists beyond a single generation. In their multi-generational study with zebra finches, the research team now examined grandmothers (generation 0), mothers (generation 1) and their children (generation 2).

Older age of breeding grandmothers results in significantly shorter telomeres ...

The study showed that the shorter telomeres found in the children of older grandmothers are also present in their children, i.e. the grandchildren generation - even if the breeding mothers of the 2nd generation were young. This effect was considerable: telomeres were 43% shorter in the offspring of grandmothers who were old at rearing than in the offspring of the same grandmothers who were young at rearing.

... and a significantly shorter life expectancy of the grandchildren's generation

“Shorter telomeres at the time of fledging are associated with a shorter lifespan in zebra finches. Our data clearly show that it is necessary to look beyond a single generation to explain inter-individual differences in ageing and different age-specific reproductive efforts,” explains study first author Valeria Marasco from the Research Institute of Wildlife Ecology (FIWI) at Vetmeduni. In the present study, the mothers were young at the time of breeding, so effects due to the age of these mothers can be ruled out. According to Marasco, however, it would also be very interesting to know whether the effects of the grandmother's age increase if the mother's age is also high.

Hidden inheritance made visible for the first time

According to the researchers, the results of the study reveal for the first time a hidden legacy that can be passed on across generations and has a negative impact on the lifespan and reproductive value of offspring. “Evolutionary biologists and ecologists therefore need to look beyond a single generation and current environmental conditions to fully understand the causes of inter-individual differences in ageing rates and age-specific reproductive effort,” says Marasco.

Better understanding of the evolution of ageing and its associated mechanisms

The researcher also emphasizes that further cross-generational research would be important. In particular, research that analyzes the lifespan and reproductive performance of the offspring of both old (grand)mothers and old (grand)fathers. Valeria Marasco: “This would improve our knowledge of the processes underlying the evolution of ageing and the diversity of life strategies within species.”

The article „Hidden Causes of Variation in Offspring Reproductive Value: Negative Effects of Maternal Breeding Age on Offspring Telomere Length Persist Undiminished Across Multiple Generations“ byValeria Marasco, Winnie Boner, Kate Griffiths, Shirley Raveh and Pat Monaghan was published in „Ecology Letters“ veröffentlicht.

Scientific article

Scientific contact:
Ass.-Prof. Valeria Marasco PhD
Forschungsinstitut für Wildtierkunde und Ökologie (FIWI)
Veterinärmedizinische Universität Wien (Vetmeduni)
Valeria.Marasco@Vetmeduni.ac.at

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