Long-term study in house sparrows shows a transgenerational age effect
Reproduction at old age involves risks that may impact ones’ own life and may impose reduced biological fitness on the offspring.
Such evidence, previously obtained in humans and other taxa under laboratory conditions, has now been confirmed by researchers from the Max Planck Institute for Ornithology in Seewiesen together with colleagues from the UK and New Zealand for the first time in free-living animals.
In a long-term study on a population of house sparrows they found that offspring of older parents themselves produced fewer young. Such a transgenerational effect is important for the understanding of the evolution of longevity.
Fertility does not decrease in all taxa with increasing age but may remain constant lifelong as is the case of some invertebrates or may even increase with increasing age as in some reptiles. Generally both sexes are able to reproduce at old age, with males capable of producing more offspring than females.
In some mammals such as humans male individuals remain fertile for a longer time compared to females that at some stage enter the menopause. However, reproducing at old age may incur risks such as a higher infant mortality or chromosomal anomalies. Moreover, children of old parents have themselves fewer offspring or have a shorter lifespan, which is commonly known as the “Lansing effect” that was demonstrated not only in humans but also in mice and some invertebrates in the laboratory but never in free living populations.
Julia Schroeder from the Max Planck Institute for Ornithology in Seewiesen has now investigated this effect in a population of house sparrows together with colleagues from the University of Sheffield and the University of Otago in New Zealand. Their study site is a small island off the coast of Devon in Southwestern England where the researchers have monitored and ringed the entire house sparrow population in the course of more than 10 years.
The researchers took blood samples from the parents and their offspring in order to determine genetic parentage. That way they obtained a unique and detailed genetic pedigree of more than 5000 birds with a precise knowledge of the age and the number of offspring for each individual. Birds stayed the entire life on this remote island that is 19 km off the coast.
During 12 years, only four sparrows could genetically not be assigned to parents living on the island, suggesting that these birds were immigrants. To test whether a possible effect is inherited or due to environmental factors entire clutches were systematically cross-fostered.
The analysis revealed a clear result. First, old mothers had a negative effect on the fitness of their daughters, meaning that these daughters produced fewer young. Similarly, older fathers produced sons that had fewer offspring. In particular, this has negative consequences for offspring that resulted from extra-pair matings, as a previous study has shown that house sparrow females seek extra-pair matings preferably with older males. Hence, according to the results of the present study, a female strategy to mate with viable males proves to be disadvantageous.
“Thus, these results cannot be explained by changes of the environment but rather by the constitution of the parents, which changes with increasing age through epigenetic processes. This transgenerational age effect may change the selection pressure on longevity within a population”, says Julia Schroeder, first author of the study. “The results are potentially important for breeding management programs of endangered species that often use old individuals from different populations to maintain genetic variability”, adds the researcher.
Dr. Julia Schroeder
Research Group Leader
Max Planck Institute for Ornithology, Seewiesen
Phone: +49 8157 932-437
Dr. Stefan Leitner
Max Planck Institute for Ornithology, Seewiesen
Phone: +49 8157 932-421
Fax: +49 8157 932-209
Julia Schroeder, Shinichi Nakagawa, Mark Rees, Maria Elena Mannarelli, Terry Burke
Reduced fitness in progeny from old parents in a natural population
Dr. Julia Schroeder | Max Planck Institute for Ornithology, Seewiesen
Zap! Graphene is bad news for bacteria
23.05.2017 | Rice University
Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine
23.05.2017 | University of California - Los Angeles
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Physics and Astronomy
23.05.2017 | Life Sciences
23.05.2017 | Medical Engineering