[Science Report]:Search for Long Life Gene


This is the VOA SpecialEnglish Science Report.

In the year Nineteen-Hundred, a baby born in the United Statescould expect to live to be about forty-nine years old. Today, thelife expectancy for a baby in the United States is seventy-sevenyears. The main reasons for this change are better food, improvedmedical care and cleaner water and waste removal systems.

Some scientists say this may explain why people live to beseventy or eighty. But only an extremely small number of Americanslive to be one-hundred years old. Many of these people have brothersor sisters older than ninety. Some scientists believe these peoplehave genes that help protect them from diseases or permit them toage more slowly than other people.

A group of researchers from Boston, Massachusetts wanted to findout more about such family groups. They studiedone-hundred-thirty-seven groups of very old brothers and sisters.One person in each group was at least ninety-eight years old. Thebrother or sister was at least ninety-one. There werethree-hundred-eight people in the study. The oldest wasone-hundred-nine years old.

The researchers say they made progress is finding the gene thatmay permit some people to live extremely long lives. The scientiststook blood samples and tested the genes of all the sisters andbrothers in the study. They compared genetic structures to findgenes that might be linked to aging. They found an area in onechromosome that appears to contain a gene or genes that may belinked to extreme old age. This one part of the chromosome hasbetween one-hundred and five-hundred genes. The scientists say it isnot clear which one or how many of the genes may affect long life.

The researchers believe the gene or genes may somehow provideresistance to disease. This may explain why many people older thanone-hundred remain healthy and active.

The researchers reported the results of their study in "TheProceedings of the National Academy of Sciences."Scientists say morework needs to be done to find the gene or genes involved in livingto be very old. They say such work could result in drugs that couldhelp people without those genes to live longer.

This VOA Special English Science Report was written by NancySteinbach.

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