Genetics & Molecular Biology
DNA is like your phone line. As Northwestern University biophysicist Johnathan Widom
put it in a talk recently, DNA simultaneously encodes multiple overlapping signals, just like your phone line that allows you to call home while you're surfing the net via DSL. Written into your DNA is the code for the amino acid sequences of the proteins produced by your genes, as well as the so-called 'non-coding' regulatory sequences which essentially encode when, where, and how much your genes are expressed.
It's easy to get lost in a eukaryotic cell. Proteins need to be in the right place at the right time to carry out their functions, but the cell is a crowded place, and the layout isn't exactly simple. Fortunately, the cell has a fairly sophisticated transportation system: if you need to head out of the cell, take the secretory pathway; if your job is to regulate genes, the nuclear shuttle will take you where you need to go.
The protein Htb2 hanging out exactly where it is supposed to be - the nucleus
Darwin didn't miss much, I think we all agree, and came up with a lot given the limited science of his day. One thing he missed, that by this time tomorrow will be the source of outrageous titles from every schlock science publication in existence, was that sexual selection that goes on even after actual sex.
Confusing? It's not so difficult to understand. Some female critters are trampy and have sex with more than one guy, for example (what, you think other parts of the animal kingdom don't have Jenna Jameson?) so there's sperm competition but there are also other factors having to do with the internal workings of the female body (i.e. that magical place), so let's catalog a few of post-copulatory sexual selection's greatest hits:
Darwin knew that some mechanism had to govern how our physical features and behavioral traits have evolved over centuries, passing from a parent to their offspring with natural selection favoring those that give the greatest advantage for survival, but he did not have a scientific explanation for this process.
Scientists for decades have believed that differences in the way genes are expressed into functional proteins is what differentiates one species from another and drives evolutionary change but no one has been able to prove it - until now, say researchers at the University of Leeds.
You age. As you age, your cells age. Your telomeres
wear out. Even single-celled yeast age, giving birth to only a limited number of daughter cells. So how is it that each new generation starts fresh, unaged?
This is a great mystery - part of which is explained by the fact that your germ cells (which later turn into sperm and egg), those cells that will produce the next generation, are preserved with extra special care right from the start of your embryonic development. The non-germ cells, called somatic cells, make up all of the rest of you, and they age.
I'm mixing my movie references with the headline, perhaps, but it's honestly the first thing that popped into my head when I read about a worm helping scientists understand longevity.
Perhaps an explanation is in order. Nicholas Wade writes
in the NY Times that germ cells (egg and sperm) are, so to speak, immortal. "A little piece of the germline’s immortality, it now seems, can be acquired by the ordinary cells of the body, and used to give the organism extra longevity."
Boys who carry a particular variation of the gene Monoamine oxidase A (MAOA), called the 'warrior' gene by some, are more likely to join gangs and be among their most violent members, according to a study from a Florida State University criminologist that associates MAOA to gangs and guns.
Findings apply only to males, which makes an unsubstantiated allele argument necessary. Girls with the same variant of the MAOA gene don't show any propensity toward gang membership or weapon use. MAOA has also been implicated in ADHD, bipolar disorder, cancer and smoking. Basically, if you don't have any other explanation for something, MAOA is the way to go.
Using single-molecule manipulation, researchers at Harvard University say they have uncovered a fundamental feedback mechanism that the body uses in regulating the clotting of blood. A new physical, quantitative, and predictive model of how the body works to respond to injury could improve treatment of bleeding disorders.
It also gives insight into how bleeding disorders, such as type 2A von Willebrand disease, disrupt this regulation system, potentially leading to new avenues for treatment and diagnosis.
One of the biggest recent breakthroughs in stem cell research is the ability to reprogram non-stem cells into stem cells using genetic engineering. The hitch with this technique is that genetic engineering like this can have side effects: stem cells produced in this way can turn into tumors in mice (and presumably humans, but we haven't tried that yet).
And thus researchers have been looking for ways to reprogram stem cells without genetic engineering. One promising way to do this is to use chemicals that can mimic the effects of the genes typically used for reprogramming. (The jargon for these genes is 'reprogramming factors' - who says technical jargon has to be opaque?)
Scientists in Portugal and France managed to follow the patterns of gene expression in food-poisoning bacteria Listeria monocytogenes (L. monocytogenes) live during infection for the first time. The work about to be published in PLoS Pathogens shows how the bacterial genome shifts to better adapt to infection by activating genes involved in virulence and subversion of the host defences, as well as adaptation to the host conditions.