Genetics & Molecular Biology

Researchers have what they think may be a basic recipe for capturing and maintaining indefinitely the most fundamental of embryonic stem cells from essentially any mammal, including cows, pigs and even humans. Two new studies reported in Cell, show that a cocktail first demonstrated to work in mice earlier this year, which includes inhibitory chemicals, also can be used to successfully isolate embryonic stem cells from rats.

Authentic rat embryonic stem cells had never before been established.
A groundbreaking study of popularity by a Michigan State University scientist has found that genes elicit not only specific behaviors but also the social consequences of those behaviors.  According to the investigation by behavioral geneticist S. Alexandra Burt, male college students who had a gene associated with rule-breaking behavior were rated most popular by a group of previously unacquainted peers.

It's not unusual for adolescent rule-breakers to be well-liked – previous research has made that link – but Burt is the first to provide meaningful evidence for the role of a specific gene in this process. The study appears in the latest issue of the Journal of Personality and Social Psychology.
At a very early stage of human development, all cells of the embryo are identical, but unlike adult cells are very flexible and carry within them the potential to become any tissue type, whether it be muscle, skin, liver or brain. 

This cell differentiation process begins at about the time that the embryo settles into the uterus. In terms of the inner workings of the cell, this involves two main control mechanisms. On the one hand, the genes that keep the embryo in their fully potent state are turned off, and at the same time, tissue-specific genes are turned on. By activating a certain set of genes, the embryo can make muscle cells. By turning on a different set, these same immature cells can become liver. Other gene sets are responsible for additional tissues.
Metaphors are dangerous things. On the one hand, it seems pretty much impossible to avoid using them, especially in rather abstract fields like philosophy and science. On the other hand, they are well known to trick one’s mind into taking the metaphor too literally, thereby creating problems that are not actually reflective of the reality of the natural world, but are only perverse constructs of our own warped understanding of it.
Asymmetry is crucial for the heart proper functioning, and now, scientists from the Institute Gulbenkian of Science in Portugal and Harvard University, have discovered that a family of genes, called Nodal, is crucial determining this asymmetry by controlling the speed and direction of the heart muscle cells during embryonic development.

The finding, by helping to understand how the heart develops, is a step closer to intervention and is of particular importance if we consider that problems in heart asymmetry are the main cause of heart congenital diseases that can affect as much as 8 out of 1000 newborns. The research appears in a special December issue of the journal Development Dynamics 1 dedicated to left-right asymmetry development.
Can science journalism get any more embarrassingly bad?

"Real-time gene monitoring developed" says a headline over at physorg.com. The piece starts off with an insane hook that makes no sense whatsoever:
With GeneVision, military commanders could compare gene expression in victorious and defeated troops. Retailers could track genes related to craving as shoppers moved about a store. "The Bachelor" would enjoy yet one more secret advantage over his love-struck dates.
Men determine the sex of a baby depending on whether their sperm is carrying an X or Y chromosome. An X chromosome combines with the mother's X chromosome to make a baby girl (XX) and a Y chromosome will combine with the mother's to make a boy (XY).

A Newcastle University study suggests that an as-yet undiscovered gene controls whether a man's sperm contains more X or more Y chromosomes, which affects the sex of his children. On a larger scale, the number of men with more X sperm compared to the number of men with more Y sperm affects the sex ratio of children born each year.
The first demonstration that a single adult stem cell can self-renew in a mammal was reported at the American Society for Cell Biology (ASCB) 48th Annual Meeting, Dec. 13-17, 2008 in San Francisco.   The transplanted adult stem cell and its differentiated descendants restored lost function to mice with hind limb muscle tissue damage.
Airline pilots who have flown for many years may be at risk of DNA damage from prolonged exposure to cosmic ionizing radiation, suggests a study in Occupational and Environmental Medicine.

The research team compared the rate of chromosomal (DNA) abnormalities in blood samples taken from 83 airline pilots and 50 university faculty members from the same US city.

The two groups were matched for age (35 to 56), sex (male), and smoking habit (light or non-smokers). Age and smoking are known risk factors for cumulative DNA damage.

Fifty eight of the pilots (70%) had served in the military, and they had undertaken significantly more personal air travel than the university staff. Both these factors would have exposed them to more ionising radiation.

How can we share 98% of our DNA with a chimpanzee and still be so different? One of the biggest biological surprises found in our genomes is that chimps, mice, and even flies don't differ very much from us in either number or types of genes. What makes the many diverse animal groups different is not what genes they have; the secret is in how those genes are used.

Something similar takes place inside ourselves: nearly every one of our cells carries the exact same DNA, and yet some cells transmit electrical signals in the brain, while others break down toxic compounds in the liver. How do you get such different cells from the same DNA? Again, the secret lies in how genes are regulated.

It should be no surprise then that gene regulation has been the subject of intense study. Most of these studies have focused on taking known genes and describing how they are regulated, but what biologists would really like to do is predict how an unfamiliar gene is controlled, simply by analyzing that gene's regulatory DNA. Once we can predict how genes are regulated, we're not far away from being able to design new regulatory DNA, which we can use to control the fate of stem cells, manipulate dosing in gene therapy, and design microbes that make better biofuels or degrade toxic waste.  A new report in Nature describes an innovative new way to learn the logic of gene regulation.