Observation in the animal kingdom
Biological forms have limitations that man dreams to overtaken by medical interventions or engineering, or a cellular rejuvenation, or cellular reprogramming.
Natural selection has developed a biological immortality in at least one species, the jellyfish Turritopsis nutricula. There are indeed living beings whose very simple biological structure and the particular mode of reproduction, allow them to be immortal. From the simplest to the most complex including bacteria, some types of yeast, Hydra and some very primitive jellyfish as Turritopsis nutricula or Turritopsis dohrnii which is currently the only known multicellular having a reversible life cycle.
Special cases: the multicellular animal more resistant to any form of external destruction , land or not, is yet considered the tardigrade, branch of separate species. The oldest trees in the world can expect to live for five millennia individually. The oldest animals have 400 years, some reptiles Tu’i Malila. Mankind has officially surpassed 120 years of life in 1995 with Jeanne Calment. Finally, some animals with neoteny (or Peter Pan syndrome) die without physiologically agedm as the axolotl, the opposite phenomenon resulting in progeria).
Turritopsis nutricula escape the normal process of cell aging, and even would reverse its growth process (which is conceivable, the structure of a jellyfish is much less complex than a vertebrate).
“Evolving often in deep water, and because they can not die, these jellyfish are currently developing their presence in waters around the world, not only in the Caribbean waters where they were originally. Dr. Maria Miglietta of the Smithsonian Tropical Marine Institute explains that “we are witnessing a worldwide silent invasion.”
Perspectives for mankind
In a book called The Death of Death, Dr. Lawrence Alexander, founder of the site Doctissimo, draws attention to the collapse of the cost of genetic sequencing in humans, much faster than for example the progress due to the Moore law, which should allow for early preventive action (in 2013, actress Angelina Jolie asked a mastectomy, when she did not have breast cancer, because of a risk suggested by the BRCA 1 gene) and effective. According to him, “the prospect of a life expectancy of 200 years at the end of this century may be a conservative assumption,” even “the first man to live 1,000 years may already be born!“, bringing her position from Aubrey de Grey. If it is not, strictly speaking, immortality, foreseeable advances in medicine during such periods can leave hope, at least technically.
There is a rare genetic disease for which the body does not seem to age at the same rate, unlike progeria. Doctors, who have not yet invented name for this syndrome, talk about biological immortality. In four cases reported in the world, their senescence process is slowed with a development almost five times longer than a normal person.
Translated and adapted from Wikipedia.