Friday November 22, 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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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)

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Mutations in Genes Associated with Heart Disease: Study

The study was presented at the 2019 American Heart Association Scientific Sessions in Philadelphia, US

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Apart from Genes, Researchers also identified lifestyle, environmental and other disease factors documented in the medical records that are associated with heart problems, like high blood pressure, diabetes, a history of alcohol or drug abuse, or previous chemotherapy treatment. Pixabay

Researchers have identified new mutations in Genes that is commonly associated with non-ischemic dilated cardiomyopathy (NIDC), a disease that weakens the heart muscle, making it more difficult to adequately circulate blood to meet the body’s needs.

Patients with NIDC struggle because the heart’s ability to pump blood is decreased, as the heart’s main pumping chamber, the left ventricle, is enlarged and dilated.

Unlike other kinds of heart conditions, NIDC often isn’t related to or a symptom or sign of a known cardiovascular disease or disease risk factor.

In the study, researchers from the Intermountain Healthcare Heart Institute in the US, have identified 22 mutations in 27 of 229 NIDC patients in a gene called TITIN — 15 of them not previously discovered.

These TITIN mutations are of a type called “truncating variants”, or TTN-tv, which are linked with the development of cardiomyopathy and heart failure.

“Truncating mutations in TITIN are common in NIDC, so we wanted to know: if we find one, should we be more, or less worried about the patient’s prognosis? The answer is yes,” said principal investigator of the study Jeffrey L. Anderson.

In the study, the DNA samples of the 229 Intermountain patients diagnosed with NIDC were analysed.

Researchers also identified lifestyle, environmental and other disease factors documented in the medical records that are associated with heart problems, like high blood pressure, diabetes, a history of alcohol or drug abuse, or previous chemotherapy treatment.

Patients were evaluated when they first presented and then were followed for five years.

Genes
Researchers have identified new mutations in Genes that is commonly associated with non-ischemic dilated cardiomyopathy (NIDC), a disease that weakens the heart muscle, making it more difficult to adequately circulate blood to meet the body’s needs. Pixabay

Patients with a TTN-tv mutation more often had severe cardiomyopathy at presentation, and by five years they were less likely to have recovered (11 per cent of those with a mutation versus 30 per cent of those without).

These patients also were more likely to have shown progressive disease, such as a heart transplant, implant of a permanent heart assist device, or death if they had a TTN-tv mutation (41 per cent) than if they didn’t (25 per cent).

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TTN-tv mutation patients also commonly were found to have non-genetic predisposing factors, suggesting that these other factors may act in concert with genetic factors to precipitate heart failure.

The study was presented at the 2019 American Heart Association Scientific Sessions in Philadelphia, US. (IANS)