Gene determines whether male body odor smells pleasant /Family dinners key to curbing teenage angst

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Gene determines whether male body odor smells pleasant

http://www.physorg.com/news109167619.html

 

To many, urine smells like urine and vanilla smells like vanilla. But androstenone, a derivative of testosterone that is a potent ingredient in male body odor, can smell like either - depending on your genes. While many people perceive a foul odor from androstenone, usually that of stale urine or strong sweat, others find the scent sweet and pleasant. Still others cannot smell it at all.

 

 

 

New research from Rockefeller University, performed in collaboration with scientists at Duke University in North Carolina, reveals for the first time that this extreme variability in people's perception of androstenone is due in large part to genetic variations in a single odorant receptor called OR7D4. The research is reported September 16 as an advance online publication of the journal Nature.

 

 

 

 

 

Androstenone, found in higher concentrations in the urine and sweat of men than of women, is used by some mammals to convey social and sexual information, and the ability to perceive androstenone's scent may have far-reaching behavioral implications for humans. In the largest study ever conducted of its kind, researchers at Rockefeller University presented nearly 400 participants with 66 odors at two different concentrations and asked them to rate the pleasantness and intensity of each odor. When scientists at Duke University identified OR7D4 as a receptor that androstenone selectively activates, Leslie Vosshall, Chemers Family Associate Professor and head of the Laboratory of Neurogenetics and Behavior at Rockefeller University and Andreas Keller, a postdoc in her lab, formed a collaboration with them, and began collecting blood samples from participants and isolated their DNA. The Duke team, led by Hiroaki Matsunami, used DNA from each participant to sequence the gene that encodes the OR7D4 receptor.

"With this large dataset, we are able to say that people who express different variants of this receptor perceive this odor differently," says Vosshall. Although it has long been suspected that the ability to perceive the odor of androstenone is genetically determined, this study is the first to identify variations in a single gene that account for a large part of why people perceive androstenone's scent so differently. With their Duke collaborators, Vosshall and Keller identified two point mutations called single nucleotide polymorphisms along the gene, which gave rise to two variants of the odorant receptor: RT and WM, which differ by two amino acids. As a group, participants with the RT/RT genotype perceive androstenone's odor as foul and intense. Those with the RT/WM genotype, on the other hand, are more likely to perceive androstenone as less unpleasant. Many cannot smell androstenone at all. Although some participants with the RT/WM genotype can smell androstenone, they experience the smell very differently than those with two copies of the fully functional receptor: To them, androstenone doesn't smell like urine; it has a vanilla scent. "There are two independent things that are interesting about this odor," says first co-author Keller. "One is that it is a potential social signal but the other one is that so many people cannot smell it." Two additional point mutations in some of the participants influenced their sensitivity to androstenone, one of which may make humans hypersensitive to this odor. Vosshall and Keller are interested in what it is about these amino acid changes that alter one's perception of androstenone's scent, and in whether one's perception of this potent compound can influence behavior. "Since some mammals clearly use androstenone to communicate sexuality and dominance within a social hierarchy, it's intriguing to think whether the same thing may happen in humans," Vosshall says. "If so, what happens to humans who can't get the signal because they have the nonfunctional copy of the gene? Or the hyperfunctional one? What could be the social and sexual implications of this on one's perception of the smell of fellow humans?" Source: Rockefeller University

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http://www.physorg.com/news109167619.html So, this may be why some men are dominant, some submissive, and most don"t respond at all. I suspect that our reliance on verbal and visual clues have lost the ability to detect the smell altogether in most of the populace. I"ve often heard it said that pheromones cannot be smelled. I know this is not so, because I"ve always been able to smell them. I can tell if a woman is jerking my chain or actually interested. I have never had to rely on what she says, only on how sweet she smells when she"s around me. I have been able to limit my advances to only those women whose body"s were advertising thier desire for me. Sure has saved a whole lot of time, money and emotional stress.

Family dinners key to curbing teenage angst

9:37AM Monday September 24, 2007By Belinda Goldsmith

http://www.nzherald.co.nz/section/6/story.cfm?c_id=6 & objectid=10465567

 

Contrary to many parents' beliefs, teenagers want to eat with the family, a study has found. Photo / Reuters

NEW YORK - Want to bond with your broody teenagers? Try eating dinner with them five times a week. A poll has found this keeps them off drugs and alcohol - and the teens also enjoy it.

The survey reaffirmed previous studies that found teenagers who ate dinner as a family five or more times a week were less likely to use drugs, smoke, or drink alcohol than peers who ate with their families twice a week or less.

But contrary to many parents' expectations, the poll of 1,063 teenagers and 550 parents, conducted by QEV Analytics, found most teenagers actually wanted to eat with their families.

"Overall about 84 per cent of the kids said they would prefer to have dinner with their parents," said Elizabeth Planet, project manager of the survey commissioned by The National Center on Addiction and Substance Abuse (CASA) at New York's Columbia University.

"These are teenagers whose parents will tell you they are difficult and don't want to talk. This is not the sense we are getting from the kids themselves. They prefer it."

 

The survey comes amid a growing push by some parents and family groups for the return of family meals which have declined sharply since the 1970s.

A UNICEF report earlier this year put the United States at the bottom of the richest nations when it came to eating as families, with only 65 per cent of 15-year-olds eating the main meal of the day with their parents several times a week. In France, Italy and Russia, it was more than 90 per cent.

The fourth CASA survey on the importance of family dinners found that 59 per cent of teens surveyed between April 2 and May 13 reported having dinner with their families at least five times a week.

 

Teens who had two or less meals a week with their family were three and a half times more likely to have abused prescription medication, three times more likely to have used marijuana, and one and a half times more likely to drink alcohol.

The teens who ate regularly with their families also got better grades, with 64 per cent reporting mostly As and Bs compared to 49 per cent of other teens.

"These statistics about the link between the likelihood of drug use and the frequency of dinners always surprises me even though we see it year in and year out," said Planet.

But for the first time they asked about the best time of day to talk, and the dinner table emerged as the favourite with nearly half of parents and teens - 47 per cent of each.

"There is nothing magical about dinner but it comes at the end of the day when you are winding down and it is a nice time for people to come together," said Planet.

"You don't see the same thing at breakfast time. Everyone is rushing out of the door."

- REUTERS