The unknown is always closer than you think. For example: what is the life expectancy of a given species of lobster, absent predators, disease and parasites? You're going to find wildly different answers if you go looking - anything from 50 to 100 years, which as good a way of admitting ignorance as any. An audio segment from NPR caught my eye today, which is why the topic is lobster longevity:

I imagine you know folks who are in their 80s, maybe in their 90s, who are sharp, lively and very active.

But here's the thing - if you were a lobster, and especially if you were a very old lobster, all your colleagues, or almost all of them, would be sharp as tacks. (Can lobsters be tacks?)

Because, as best scientists can tell, lobsters age so gracefully they show no measurable signs of aging: no loss of appetite, no change in metabolism, no loss of reproductive urge or ability, no decline in strength or health.

Lobsters, when they die, seem to die from external causes. They get fished by humans, eaten by seals, wasted by parasites, but they don't seem to die from within. Of course, no one really knows how the average lobster dies. There are no definitive studies.

Absent signs of aging have traditionally made it hard to determine age in zoological studies:

To date, there is no proven method to determine the exact age of a lobster. Scientists and experts can only guess at a lobster's age; this is based on water temperature, geographical location, and other factors. On average, it takes approximately 5-7 years for a lobster to reach 455 grams (the traditional 1 pound minimum legal size). It is believed, however, that in the wild lobsters can approach 100 years or more in age.

I believe that greater awareness of the many species that age very slowly or are of great longevity compared to their peers - turtles, tortoises, whales, rockfish, and so on - will help increase support for healthy life extension research in humans. Aging is not set in stone, immutable, and these are examples of that fact. Aging is radically different for different species, and therefore open to change. Other configurations of biochemistry can do far better than ours, which means that this modern age of biotechnology should be capable of enabling us to live longer in good health, if we but set our minds to the task.

Looking back in the medical research archives, I stumbled on research from a decade ago that suggests lobsters sustain their undiminished vitality through maintenance of long telomeres:

Longevity of lobsters is linked to ubiquitous telomerase expression

Mammals have high growth rates in embryonic and juvenile phases and no growth in adult and senescent phases. We analyzed telomerase activity in a fundamentally different animal which grows indeterminately. Lobsters (Homarus americanus) grow throughout their life and the occurrence of senescence is slow. A modified TRAP assay was developed and the lobster telomeric repeat sequence TTAGG was determined.

...

High telomerase activities were detected in all lobster organs. We conclude that telomerase activation is a conserved mechanism for maintaining long-term cell proliferation capacity and preventing senescence, not only in cellular models or embryonic life stages but also in adult multicellular organisms.

All most interesting, the things we don't yet know.

Technorati tags: aging

Posted by Reason at June 27, 2007 9:44 PM | TrackBack (0)