I have enjoyed a much needed break, but I could not fully forget about the blog and a few current events. Many of you have asked me for my reaction to the meeting between Patriarch Kirill and Pope Francis but at the time I decided not to comment about it. The time just did not feel right and I was not ready for it.
Our closest relatives, whose onset of aging occurs considerably earlier than in humans Old world monkeys 23 Mya 3.
Last common ancestral represents estimates--often still under debate--of when a species and humans split, in millions of years ago Mya. See Finch, ; Hill et al.
Some gerontologists that defend multifactorial causes of aging previously argued against a molecular clock regulating cellular senescence e.
Now we know that indeed such a clock exists, as detailed in another essay. A complex cascade of events such as cellular senescence can be regulated by a few genes such as telomerase Bodnar et al. While no doubt organismal aging is more complex and under the regulation of more genes than cellular senescence, the point is that aging is not merely random deterioration but must entail mechanisms under the regulation of the genome; whether these mechanisms actively cause aging, like certain mechanisms cause cell senescenceor merely regulate systems, such as repair processes, that end up modulating aging is discussed elsewhere.
Like for other continuous traits--phenotypes that can be measured on a quantitative scale-- aging is multifactorial in the sense that it is influenced by many genes interacting with the environment. Indeed, it has been long acknowledged that extrinsic factors Progeria essay conclusion important in aging Rowe and Kahn, What has surprised scientists in recent years is the extent and number of genes that can influence aging, as detailed below.
How Genes Can Regulate the Aging Process The greatest evidence in favor of seeing aging as having a unifying core is the way single genes can modulate the aging process.
The plasticity of lifespans in invertebrates shows how one or a few genes can regulate the entire aging process Lin et al. For example, in worms, single gene mutations can extend lifespan by almost fold Ayyadevara et al.
These results clearly argue that genetic mechanisms can, up to a certain degree, regulate aging in mammals. These genes and their mechanisms are further detailed elsewhere. Human studies have shown a significant degree of heritability of longevity, in particular at later ages Hjelmborg et al.
Studies in centenarians, in fact, have shown that the offspring of long-lived parents are protected against age-related diseases for example see Atzmon et al. Genetic variants alleles in human homologs of genes shown to regulate aging in model organisms have also been associated with human longevity Bonafe et al.
In fact, and in spite of individually having a small effect, dozens of genetic variants have been associated with human longevity, as compiled in our LongevityMap database Budovsky et al.
Lastly, it has been argued that the rapid evolution of longevity in the human lineage indicates that maybe a small number of genes are able to regulate the pace of aging Cutler, One of the most intriguing phenotypes in the biology of aging is the accelerated aging witnessed in humans and animals as a result of certain mutations.
Progeroid syndromes, as they are called, are rare genetic diseases that originate a phenotype that resembles accelerated aging. Though patients with Down syndrome or trisomy 21 often also exhibit progeroid features Martin, ; Raji and Rao,this disease has not gathered as much attention from the perspective of aging research as the other three syndromes named above.
In particular patients with WS exhibit striking features resembling accelerated aging and show an early onset--compared to normal aging--of multiple age-related diseases like diabetes, cataracts, osteoporosis, baldness, and atherosclerosis Goto, ; Fig.
Though differences exist in terms of pathology, what most markedly distinguishes these syndromes is age of onset with Hutchinson-Gilford's and Cockayne syndrome almost exclusively affecting children while WS patients normally reach adulthood.
There are also five reported cases of a neonatal form of progeria called Wiedemann-Rautenstrauch syndrome, in which babies appear to be born old, but further research is needed to confirm or dismiss such cases as accelerated aging Rodriguez et al.
This is a high proportion since it is not clear that these diseases are indeed accelerated aging. Such diseases demonstrate the hierarchical essence of aging in which a single gene can regulate a vast array of complex age-related changes. Further details concerning the underlying molecular mechanisms of these diseases are presented in another essay.
A Werner syndrome patient. One key discovery in the biology of aging was made infollowing earlier findings Osborne et al. As previously mentionedthey discovered they could slow aging in laboratory rats just by making them eat less calories while maintaining normal levels of proteins, vitamins, and minerals McCay et al.
This process became known as caloric restriction CR and appears to work in many animals; it has been particularly well-studied in mice. Doubts have for long existed on whether CR results from some technical artifact. Even so, CR remains the most impressive way to delay aging in mammals, particularly since it derives from a quite simple intervention.
Like WS, CR demonstrates how it is possible to delay the aging process as a whole, suggesting that aging has a unifying clock. The mechanisms of CR are still under debate but are further discussed in another essay.Is Aging Genetic or Is It Wear and Tear?
Aging has been compared to the natural decay of materials and objects. In this essay, I debate the essence of the aging process and hope to demonstrate that, despite any initial appearances, human aging is not simply wear and tear. Jun 26, · Introduction In this assignment I am going to compare some areas of molecular revolution with genomics revolution.
Cyril Darlington (ï¿½) was the most famous cytologist in the world in the decades preceding the molecular revolution of the s. The American Journal of Clinical Nutrition is a peer reviewed journal from the American Society of Nutrition that publishes original research studies relevant t.
I think it is western scientific culture that presents an aberrant world view, that shuns man’s inherent mystical state. In almost all cultures it is acknowledged that their is . Dynamically updated essay by Vincent Giuliano on theories of aging and protective firewalls.
serious and humerous. Subjects include longevity, health, anti-aging. Dynamically updated essay by Vincent Giuliano on theories of aging and protective firewalls.
serious and humerous. Subjects include longevity, health, anti-aging.