The scientific community has long observed in different species, including humans, that the offspring of younger parents tend to live longer than the offspring of older parents, but this phenomenon, called the ‘Lansing effect’, has proven difficult to document experimentally. Now, researchers from the University of Vigo in collaboration with the University of Glasgow, in Scotland, have demonstrated the existence of this effect in birds. Using zebrafish and a controlled reproduction design, the researcher from the Animal Ecology group of the Marine Research Center of the University of Vigo, José C. Noguera, has shown that as parents age, especially older ones, they produce offspring with a shorter lifespan. These findings, recently published in the prestigious journal Proceedings of the Royal Society of London B, also show a possible genetic mechanism involved in this ‘Lansing effect’, the shortening of telomeres – repetitive DNA sequences that cover the ends of chromosomes and play an important role in cellular aging and the prevention of chromosomal degradation.
“The offspring of elderly parents frequently show lower longevity, although the mechanisms that give rise to this Lansing effect are still unknown,” explains the researcher from Vigo, to which he adds that although inheriting shorter telomeres from older parents could be a mechanism that explains it, “since telomere length is a good predictor of life expectancy in some species,” the studies carried out to date in different species have not found conclusive results. “On the contrary, most of the evidence that exists comes from non-experimental studies in which it is difficult to exclude various sources of error,” emphasizes Noguera, who also warns that it is difficult to extrapolate the results to other species.
Investigating the relationship between DNA and life expectancy
The study, which has just been published, provides evidence supporting the existence of the ‘Lansing effect’ in this species and demonstrates that the reduction of telomere length during the embryonic phase could be an important mechanism determining this phenomenon. On the one hand, they carried out a longitudinal study that showed that the longevity of the offspring was negatively related to the age of the father at the time of reproduction. Then, as a second step to unravel the possible causes, they used an experimental approach to examine whether or not prenatal paternal effects on telomere length could be detected in the offspring. “We found that zebrafish embryos sired by old males had shorter telomeres than embryos produced by the same mothers when they were bred with young males,” notes the researcher.
Given that variation in embryonic telomere length persists during the postnatal period in this species and that individuals with shorter telomeres show shorter life expectancy, the study demonstrates that a paternally driven reduction in telomere length could, at least in part, underlie the reduced life expectancy in children of elderly parents.
The study lasted for five years
To conduct this study, the team formed 44 pairs of male and female zebra finches. They then tracked the survival of one offspring from each pair. The percentage of surviving offspring from older parents, the researchers found, dropped dramatically to less than ten percent within the first 16 months. Meanwhile, the percentage of surviving offspring from younger parents declined slowly but steadily over the course of about five years.
In another phase of the study, the team worked with a separate group of zebra finches, pairing each of the 32 females with a young male about four months old or an older male four years old. In a second round of breeding, they paired the same females with males from the alternate age group. They extracted genetic material from the resulting embryos and measured the length of their telomeres. That’s how the team found that zebra finches from older parents had shorter telomeres.
Source:DUVI
