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Evolution of the Human Lifespan

 Evolution of the Human Lifespan



The question of the limits of life expectancy is a central concern for societies around the world. As the population ages, the burden of ill health and mortality falls disproportionately on the elderly. Longer life spans and decreasing birth rates also result in an increased ratio of dependent to independent members of society. Both of these trends pose huge economic challenges. Nowadays, there are people are also curious to know about
lifespan of idiots as well. Current demographic trends suggest that life expectancy will continue to increase in all countries, but when the limit of the human lifespan will be reached is largely a mystery.

Extrinsic mortality

The theory of evolution predicts that higher extrinsic mortality rates lead to shorter human lifespans. Higher extrinsic mortality rates should limit the development of pro-longevity mutations and lead to lower overall lifespans. However, if extrinsic mortality rates were low and correlated with the rate of natural selection, the evolution of longer human lifespans may proceed smoothly.

Genetics

Biological changes occur during the course of our lives. While some traits are inherited, others are influenced by our environment. Genetic variation begins during the fertilisation of the egg by several million sperm. Humans have 23 chromosomes, or genes. Inheritance of a trait depends on several factors, such as the number of copies of a gene and how they have been modified. During meiosis, the cell divides into two copies, each with different sets of chromosomes.

Environment

Earlier in history, we argued that environment influences the evolution of human lifespan. However, modern studies suggest that our life expectancy has increased only slightly in the last 100 years. Although we are now living longer lives than we did in the past, the average human lifespan is still considerably shorter than that of wild chimpanzees. This apparent species difference may be due to a higher immune response. Now, however, the evidence suggests that both our life expectancy and fertility are related.

Lifestyle

Many researchers have proposed that lifestyle evolution is linked to a longer human lifespan. It's true that life spans can vary greatly across species, but the common genetic variability accounts for 25 percent of the variation in human lifespan. If this hypothesis is correct, then we may be able to use our genetics to modulate our lifestyle. Specifically, we can choose genes that will enhance our metabolism or response to stress. In addition, some studies suggest that lifestyle modification is related to longer life spans among humans. And while epigenetic factors are not yet fully understood, they will likely gain importance as biomarkers and targets in the future.

Pleiotropy

In 1957, G.C. Williams proposed an antagonistic model of pleiotropy in the evolution of the human lifespan, where the force of natural selection reduces with age, favoring genes that enhance fitness early in life but have less favorable effects as we age. In a similar manner, a combination of pleiotropic and antagonistic genes may lead to a decline in health as we age. More recent studies have taken a less genetic approach to aging and recognize trade-offs in the development of related characters and traits.

APOE/TOMM40

Recent research suggests that common variants in the TOMM40/APOE/APOC1 genes may be responsible for longevity. This association study focused on these three genes. Among the SNPs studied, rs2075650 was found to be highly associated with human longevity. Furthermore, it was found to be in LD with rs429358. Thus, rs2075650 may be a good proxy for rs429358.

CpG density

A recent study found a strong correlation between the human lifespan and CpG density among vertebrate species. This correlation was statistically significant across all vertebrate classes and may be taxon-specific. Mammals exhibited the strongest correlation, but that may be because of the promoters' involvement in the project. Furthermore, mammals are the most recent vertebrate class, with less divergence time. Moreover, you may also know stay connected to the facts related blogs to explore such topics.

 

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