How fast you age depends on your parents

The genetic make-up of our cells consists of genes lined up on chromosomes. The ends of the chromosomes are called telomeres, and they protect the chromosomes from sticking to each other. The longer the telomeres, the longer the chromosomes are able to function. And conversely, the shorter these ends, the less time left for the chromosomes, and thereby also the cells, to be in working condition. More knowledge of telomeres can therefore be valuable in understanding the aging process in humans and other animals.

In the present study, researchers from Lund University looked for explanations of the variation in telomere length in newborn individuals. It is an obvious advantage to start life with longer telomeres rather than short ones.

“It is remarkable that so early on in life, there are already such major differences between individuals, both in humans and in animals”, says Asghar Muhammad, one of the researchers behind the study.

The researchers used data from a 30-year-long study of ringed great reed warblers at lake Kvismaren, south central Sweden. The aim of the study was to find out which hereditary factors affect the length of the chromosome ends in chicks. Thanks to the long series of measurements, it was possible to compare the length of telomeres in newborn individuals with that of their parents when these were newly hatched chicks.

The results showed that the length of the telomeres in this songbird depends on a fairly even distribution of hereditary and non-hereditary factors. It appears that the older the female is at the time of the chicks’ birth, the longer their chromosome ends will be. The non-hereditary factors consist of various aspects connected specifically to the female, not to the male. For example, the female can affect the hormone levels or antibodies in the egg yolk which the chick ingests even before hatching.

Asghar Muhammad observes that the great reed warblers differ from humans in this, as previous research has shown that the non-hereditary factors which are significant to chromosome ends in human offspring are connected to the father rather than the mother.

“In humans, there is a link between the father’s age and the length of the child’s telomeres. The older the father, the longer the telomeres” says Asghar Muhammad.