Tuesday July 23, 2019

Your Genes May Not Help You Live Long

The answer might lie in assortative mating. People tend to select partners with traits like their own -- in this case, how long they live, they explained

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genes
Gene triggering antibiotic reaction risk identified. Pixabay

Although long life tends to run in families, genes has far less influence on life span than previously thought, according to a new analysis of an aggregated set of family trees of more than 400 million people.

The study suggests that the heritability of life span is well below past estimates, which failed to account for our tendency to select partners with similar traits to our own.

“We can potentially learn many things about the biology of ageing from human genetics, but if the heritability of life span is low, it tempers our expectations about what types of things we can learn and how easy it will be,” said lead author Graham Ruby, from Calico Life Sciences — a US-based research and development company.

“It helps contextualise the questions that scientists studying ageing can effectively ask,” she added

Heritability measures how much life span can be explained by genetic differences, excluding differences like lifestyle, sociocultural factors and accidents.

While previous estimates of human life span heritability have ranged from around 15 to 30 percent, in the new study it was likely no more than seven per cent, perhaps even lower.

For the study, published in the journal Genetics, the team used online genealogy resource with subscriber-generated public family trees representing six billion ancestors.

Each of them was connected to another by either a parent-child or a spouse-spouse relationship. Pixabay

Removing redundant entries and those from people who were still living, they stitched the remaining pedigrees together included more than 400 million people, largely Americans of European descent.

Each of them was connected to another by either a parent-child or a spouse-spouse relationship.

They focused on relatives who were born across the 19th and early 20th centuries, and noted that the life span of spouses tended to be correlated, more similar than in siblings of opposite gender.

Comparing different types of in-laws, they found that siblings-in-law and first-cousins-in-law had correlated life spans, despite not being blood relatives and not generally sharing households.

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The finding that a person’s sibling’s spouse’s sibling or their spouse’s sibling’s spouse had a similar life span to their own made it clear that something else was at play, the researchers said.

The answer might lie in assortative mating. People tend to select partners with traits like their own — in this case, how long they live, they explained. (IANS)

Next Story

Third-Hand Smoke can Harm Respiratory System by Changing Gene Expressions: Study

A total of 382 genes among approximately 10,000 genes in the data set were significantly over-expressed and seven other genes were under-expressed, according to the study

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third-hand smoke
The nasal membrane tissue is similar to those in the bronchus, so the researchers suggested that the damage could go deeper into the respiratory system. Flickr

The hazards of second-hand smoke are well-known. Now, scientists have found even third-hand smoke (THS) could do harm to one’s respiratory health by changing gene expressions.

The study published in the latest edition of JAMA Network Open this week showed that the third-hand smoke can damage epithelial cells in the respiratory system, coercing those cells into a fight for survival, Xinhua news agency reported. THS results when the exhaled smoke and smoke emanating from the burning cigarettes settle on surfaces like clothing, hair and furniture.

The researchers from University of California, Riverside (UCR) obtained nasal scrapes from four healthy non-smoking women aged 27 to 49 years, who were randomized to receive the clean air exposure first and then THS exposure for three hours. The researchers extracted Ribonucleic Acid (RNA) from them to examine their gene expression changes.

third-hand smoke
Also, the researchers have found that the inhalation altered pathways associated with oxidative stress that may cause cancer in the long term. Flickr

A total of 382 genes among approximately 10,000 genes in the data set were significantly over-expressed and seven other genes were under-expressed, according to the study. “The THS inhalation for only three hours significantly altered gene expression in the nasal epithelium of healthy non-smokers,” said the paper’s first author Giovanna Pozuelos, a graduate student at UCR.

ALSO READ: Researchers Discover Extremely Harmful Levels of Toxins Found in Enamelled Decoration of Beer and Wine Bottles

Also, the researchers have found that the inhalation altered pathways associated with oxidative stress that may cause cancer in the long term. The nasal membrane tissue is similar to those in the bronchus, so the researchers suggested that the damage could go deeper into the respiratory system.

“Many smoking adults think, ‘I smoke outside, so my family inside the house will not get exposed.’ But smokers carry chemicals like nicotine indoors with their clothes,” said Prue Talbot, a professor at UCR, who led the research. “It’s important to understand people that the THS is real and potentially harmful,” said Talbot. (IANS)