Some studies show that telomere shortening has been caused by stress, but until now, no study has been completed which suggests that social isolation has an effect on telomere shortening. Telomeres shorten during cell division and once a certain length is reached, the division stops – this is termed “replicative senescence.” Senescence helps in eliminating old cells but contributes to aging and mortality.
To test the effect of social isolation on telomere shortening, Denise Aydinonat, a doctorate student at the Vetmeduni Vienna, conducted a study on African grey parrots. These parrots are highly social birds, but in captivity they are kept in isolation. Denise used DNA samples of the birds for the test. She and her team compared telomere lengths of single birds and pair-housed individuals of varying ages from 1-45 years old. As expected, telomere lengths of older birds were shorter than the younger birds regardless of the housing situation. But the revealing discovery was that the telomeres of single-housed birds were shorter than the pair-housed ones of the same age group.
This is the first study of a specific species to show the detrimental effect of social isolation on telomere length. Dustin Penn from the Konrad Lorenz Institute of Ethology at the Vetmeduni Vienna conducted an experiment on mice to show that stress in overcrowding also shortens telomeres on the subject. Looking at both experiments, we can see that both extremes of social conditions lead to shortening of telomeres. This finding is important as it shows that telomere length can be used as a 'biomarker' to determine an individual's exposure to chronic social stress.