Scientists identify new genetic variants linked with human height
While the genetic contributions to height have always been recognized, only recently have scientists begun to identify specific genetic variants dictating an individual’s height.
Height is thought to be the product of variations at multiple genes, each producing a minor contribution. Researchers from The Children’s Hospital in Philadelphia embarked on a genetic study of over 100,000 individuals in an attempt to identify variants contributing to adult height. Their method involved genotyping each individual, leading them to uncover 64 height-associated variants.
The scientists analysed the genomes by studying single nucleotide polymorphisms, or SNPs, which are a change in only one nucleotide of the genetic code. By genotyping uncommon SNP arrays — with a frequency of less than 5 per cent — new disease variants can be discovered, which could have been previously missed using common SNP arrays. However, these variants occur at a low frequency, which is why a large sample size is critical to detect them. Interestingly enough, these low-frequency variants actually have a greater independent effect than some of the more common variants.
This large collaborative study was published in the American Journal of Human Genetics.— Nardin Samuel
Source: Cell Press
Brain activity linked to likelihood of quitting smoking
Want to quit smoking, but think you can’t? A new study from the University of Michigan suggests that what you think may not necessarily correspond with your actual likelihood of quitting smoking.
Researchers took 28 heavy smokers and had them watch pro-health TV advertisements aimed at helping people quit smoking. They used fMRI, a scanning technology that measures brain activity, to see how the study participants responded to the ads. After seeing each ad, they also had the subjects rate how it affected their intention and confidence regarding quitting.
To follow up, the researchers contacted the participants one month after the scan to see how much they were smoking, and validated these reports by measuring the levels of carbon monoxide in their blood. Compared to smoking an average of 21 cigarettes a day before the study, participants reported smoking five cigarettes afterwards, which was consistent with measured carbon monoxide levels.
The researchers found a positive relationship between brain activity and quitting smoking, even in those participants who negatively predicted their likelihood of quitting. The principal investigator of the study, Emily Falk, commented, “It seems that our brain activity may provide information that introspection does not.”— Mina Park
Source: National Science Foundation
