Genetics & Molecular Biology
After eight years and I am still learning new things my husband: we were walking down the street yesterday when the clouds parted, revealing a bright sun and he consequently sneezed! Now I realize that this phenomenon affects a significant number of other people I know. So in case you were ever wondering why looking at the sun on a bright day makes you sneeze here is the answer:
University of Iowa researchers have learned more about a genetic mutation that contributes to autism. The mutation occurred in sperm cells of a father, who does not have autism, but passed the condition on to two of his children.
The identification of a cluster of essential genes on mouse chromosome 11 as well as similar clusters on the chromosomes of other organisms – including humans – buttresses the argument that there may be rules as to how genes are structured or laid out on chromosomes, said the Baylor College of Medicine senior author of a report that appears online today in the Public Library of Science Genetics, an open-access publication.
Last fall I had a chance to hear a presentation by Doug Berg
, a microbiologist here at Washington University. Berg's work is a great combination of new technology, genomics and evolution, and it happens to also have potential medical relevance. He's studying the evolution of drug resistance in Helicobacter pylori,
a usually benign bacterium that is responsible for stomach ulcers. (Recall that the Nobel Prize
in medicine was awarded in 2005 to Barry Marshall and Robin Warren for their discovery of the link between H.
Traditionally, the genome has been viewed as a collection of DNA molecules that vary in composition between individuals and species, and variations that generate phenotypic differences have been assumed to occur in a more or less random manner. More recently, this view has been challenged by evidence that genomes are in fact reservoirs of adaptive phenotypic plasticity. This adaptive genome concept, where mutations that convey adaptive benefits are likely to occur at greater than random frequencies (Caporale 1999, 2000, 2003) represents a synthesis of ideas and evidence from several subfields and has its genesis in work by pioneers such as Dhobzhansky (1937), Dawkins (1976), McClintock (1984) and Trifinov (1989).
Just recently Science
published the paper describing the latest primate genome - the rhesus macaque genome. (Check out Science's macaque website
for some good (and free) articles on the subject.) Sequencing a large genome like this one is resource intensive (unlike microbial genomes, which are now easily and routinely sequenced), so why did scientists sequence yet another primate genome? In addition to the human genome we already have the chimp genome, and we also have several non-primate mammalian genomes - the mouse, rat, cow, dog, and opossum genomes. Is this a good use of our money?
The largest study to date of genetic variation among chimpanzees has found that the traditional, geography-based sorting of chimps into three populations—western, central and eastern—is underpinned by significant genetic differences, two to three times greater than the variation between the most different human populations.
Researchers have discovered that the genetic malfunction that causes a form of mental retardation called Noonan Syndrome (NS) produces an imbalance in the genesis of two types of cells in the developing embryonic brain. This imbalance, they theorize, could explain how the genetic abnormality gives rise to the neural pathology of the disorder. More broadly, they said, the new insight into the mechanism underlying NS could apply to other inherited forms of retardation.
For the growing number of people with diminished immune systems - cancer patients, transplant recipients, those with HIV/AIDS - infection by a ubiquitous mold known as Aspergillus fumigatus can be a death sentence.
The fungus, which is found in the soil, on plant debris and indoor air, is easily managed by the healthy immune system. But as medical advances contribute to a growing population of people whose immune systems are weakened by disease or treatment, the opportunistic fungus poses a serious risk.
I rubbed the belly of the Gene Genie
, and it revealed unto me that I shall search the OMIM database with the term "nine
". So, let's venture into the unknown expanse of the human genome (cue some Carl Sagan space documentary music).