Archive for August 5th, 2012
Mental disabilities stemming from Fragile X and Down syndrome involve similar molecular pathways, according to a new study published in The EMBO Journal.
Both disorders are characterized by problems with the processes that regulate the way nerve cells develop dendritic spines—the small protrusions on the surface of nerve cells that are vital for communication in the brain.
“We have shown for the first time that some of the proteins altered in Fragile X and Down syndromes are common molecular triggers of intellectual disability in both disorders,” said Kyung-Tai Min, a professor at Indiana University and the Ulsan National Institute of Science and Technology in Korea.
“Specifically, two proteins interact with each other in a way that limits the formation of spines or protrusions on the surface of dendrites.”
“These outgrowths of the cell are essential for the formation of new contacts with other nerve cells and for the successful transmission of nerve signals. When the spines are impaired, information transfer is impeded and mental retardation takes hold,” he said.
Two of the most common genetic causes of intellectual disability are Fragile X and Down syndromes.
Fragile X syndrome is triggered by a single gene mutation that prevents the production of a protein needed for proper neural development (Fragile X mental retardation protein). For Down syndrome to occur, all or a part of a third copy of chromosome 21 must be present.
Although each syndrome is due to a separate genetic difference, the researchers identified a shared molecular pathway in mice that triggers intellectual disability in both disorders.
Down syndrome mice models have difficulties with memory and brain function, and the development of the heart is often compromised, symptoms that are also observed in humans with Down syndrome.
“We believe these experiments provide an important step forward in understanding the multiple roles of DSCR1 in neurons and in identifying a molecular interaction that is closely linked to intellectual disability for both syndromes,” said Min.
Source: The EMBO Journal
New research finds that playfulness and a sense of humor are important traits sought in romantic partners.
Researchers at Penn State University liken playful behavior and a sense of humor to bright plumage on birds to attract a mate.
“Humans and other animals exhibit a variety of signals as to their value as mates,” said professor Garry Chick.
“Just as birds display bright plumage or coloration, men may attract women by showing off expensive cars or clothing. In the same vein, playfulness in a male may signal to females that he is nonaggressive and less likely to harm them or their offspring. A woman’s playfulness, on the other hand, may signal her youth and fertility.”
Chick and his colleagues expanded on a previous survey that included a list of 13 possible characteristics that individuals seek in prospective mates. To the original list, they added three new traits: “playful,” “sense of humor” and “fun-loving.” The authors gave the survey to 164 male and 89 female undergraduate students, ages 18 to 26.
Of the 16 items, “sense of humor,” “fun-loving” and “playful” ranked second, third and fourth, respectively, among traits that females sought in males. Males rated three traits — “physically attractive,” “healthy,” and “good heredity,” all characteristics of female fertility — significantly higher than women.
“The fact that the subjects tended to rank ‘sense of humor,’ ‘fun-loving’ and ‘playful’ at or near the top of the list of 16 characteristics does not mean that the mates they have selected or will select will actually exhibit these traits,” said Chick.
“In addition, the results may be skewed by the fact that most of the study subjects were college students from a Western culture. Despite these caveats, it seems to us that signaling one’s virtues as a potential long-term mate through playfulness is not far-fetched. Our results suggest that adult playfulness may result from sexual selection and signal positive qualities to potential long-term mates.”
Source: Penn State