Longevity: Introductory Notes

April Barnado

“All the world’s a stage. And all the men and women merely players: They have their exits and their entrances; And one man in his time plays many parts, His acts being seven ages…Last scene of all, that ends this strange eventful history, is second childishness and mere oblivion. Sans teeth, sans eyes, sans taste, sans everything.”

~Shakespeare, from As You Like It

Image used from Microsoft Word Clip Art, Windows XP Professional.

As Shakespeare’s fateful lines indicate, many of us will have to face the “last scene of all” and deal with aging and its accompanying debilitating processes. The search for the “fountain of youth” and bodily perfection is still strong in our society as shown by the abundant anti-aging remedies and continual advertisement of ways to reverse the signs of aging to feel, look, and act young again.

In this search, science, particularly the field of genetics, has been looked to extend longevity. However, in this search, science has been exploring the following questions: What causes us to age? Is there a “longevity gene” or “old age gene” that makes some people live longer than others? What role do our genes versus our environment play in determining how long we live? If scientists were able to manipulate the aging process, how long would a person want to live? How would one balance quantity versus quality of life?

The “Biology of Aging” section will provide information on the biological theories that try to explain why and how we age. The “Future” section will explore the current research and progress on these theories and on the search for “longevity genes.” This section will also include a brief discussion of ethical implications and a link to more ethical considerations concerning longevity.

Definitions of Important Terms

As our society seeks for bodily perfection and the fountain of youth, basic terminology of life expectancy and life span become construed and lumped together. Here are some definitions of those terms offered by the scientific community:

Life expectancy – “is the average total number of years that a human expects to live”(Hayflick, 2000).

Life span – “the maximum number of years that a human can live”(Hayflick, 2000).

For other definitions of other important biology terms, please click on the underlined, linked words within the text to see a brief definition or please see the following link for a list of all defined terms.

Davidson College Survey Results

Introduction

A survey composed by a group of the Davidson College Biology Senior Colloquium class was sent via email to 250 people consisting of randomly selected Davidson students, professors, and staff. These persons are of a variety of majors or teach or work in a variety of academic and nonacademic departments. There were approximately 121 respondents with a response rate of 48.4% with the following demographics:

For more details on the survey, please see the Introduction page to Genetics.

Demographics

• Age

• Sex

• Ethnicity

Questions and Opinions on Longevity

Survey respondents answered a total of twelve questions on the pursuit of bodily perfection in terms of genetic perfection. Within the area of genetic perfection, there were two questions regarding views on longevity and its link to genetics.

How strongly does a person’s genetic make-up determine how long he or she will live?

A vast majority of the respondents, almost 92%, expressed that genetics has a very strong to moderately strong influence on human longevity. This very high percentage may reflect some biological knowledge concerning genetics and longevity but also may reflect an influence of the media’s widely communicated view that our genes “absolutely control” how long we live. The media continues to cover “breaking news” on the discovery of the “longevity gene” and the false implications of this discovery enabling humans to achieve immortality. Interestingly, no respondent choose the “absolutely control” option or the other extreme that a person’s genetic make-up does not control how long he or she will live. Thus, there seems to be a reasonable and accurate understanding that both genetics and environmental factors influence how long a person will live.

If technology became available, how long would you want to live?

There was a variety in responses to how long the respondent would want to live if technology became available. An overwhelming number of approximately 94.2% choose to live beyond the average life span range of 70-80. A majority of 66.7% wanted to live just past the average life span in the range 80-100 while 28.1% wanted to live in the upper range of longevity of 100-120+. Interestingly, 13.2% wanted to live to 120 or more years. These responses are spread over all the age ranges probably due to the differences in age of the respondents and different experiences with relatives or friends who were undergoing the aging process. Due to experiences with relatives or friends undergoing aging and possibly suffering the debilitating diseases that accompany aging, some respondents may value quality versus quantity of life. On the other hand, others may want to push the limits of longevity and value quantity versus quality of life.

Questions or Comments: Email Dr. Verna Case

Davidson College Biology Department

Davidson College

This web page was produced as an assignment for an undergraduate course at Davidson College.

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