European Seabirds Shed Light On Why Older Parents' Offspring Have Shorter Lives
The European shag, which is a long-lived seabird, may provide clues as to why older parents give birth to offspring who tend to live shorter lives. It turns out that the answer to this long-standing mystery may be related to one's DNA and post-natal care, researchers say.
In the latest study, Britt J. Heidinger, an assistant professor of biological sciences at North Dakota State University (NDSU), and colleagues in Scotland found the length of an offspring's telomeres - protective caps at the ends of chromosomes - greatly influence longevity.
"Telomeres function a bit like the plastic caps at the ends of shoelaces and protect the coding DNA from loss during cell division. Telomere loss reduces the lifespan of cells and is thought to be involved in the aging process," Heidinger explained in a news release.
On the other hand, individuals with longer telomeres, or slower rates of telomere loss, have been shown to have greater longevity in a wide range of species.
However, researchers were interested to see whether offspring inherit shorter telomeres from older parents or if they simply experience more telomere loss during pre- or post-natal growth. To find out, researchers experimented on a free-living population of European shags (Phalacrocorax aristotelis) that breed on the Isle of May National Nature Reserve in the Firth of Forth, Scotland. This is an estuary of the River Forth, and is near Edinburgh. These socially monogamous seabirds can live to be 22 years old. Small blood samples were collected from recently-hatched chicks to measure their telomere length.
Overall researchers found chicks produced by older mothers and fathers had significantly greater telomere loss than chicks produced by younger parents, but the loss occurred during nestling growth, rather than during the pre-natal period, researchers explained. This suggests reduced longevity is more related to after-birth stress, than to genetics.
"We have previously found that shag chicks that experience higher levels of stress during development have greater telomere loss," Heidinger added in the university's release. "These results could have occurred because older parents do not provide as much parental care as younger parents, or because parents that put less effort into raising their chicks live to be older."
Their findings were recently published in the journal Functional Ecology.
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