Two recent articles in TiGS by Gerald Crabtree float the notion that we, as a species, are gradually declining in average intellect because we are accumulating mutations that deleteriously affect brain development or function. The observations that prompted this view seem to be: (i) intellectual disability can be caused by mutations in any one of a very large number of genes; and (ii) de novo mutations arise at a low but steady rate in every new egg or sperm. He further proposes that (iii) genes involved in brain development or function are especially vulnerable to the effects of such mutations. Considered in isolation, these could reasonably lead to the conclusion that mutations reducing intelligence must be constantly accumulating in the human gene pool. Thankfully, these factors do not act in isolation.

If we, as a species, were simply constantly accumulating new mutations, then one would predict the gradual degradation of every aspect of fitness over time, not just intelligence. Indeed, life could simply not be sustained over evolutionary time in the face of such genetic entropy. Fortunately (for the species, although not for all individual members), natural selection is an attentive minder. […]

Whether causally or as a correlated indicator, intelligence is strongly associated with evolutionary fitness, even in current societies. The threat posed by new mutations to the intellect of the species is therefore kept in check by the constant vigilance of selection. Thus, despite ready counter-examples from nightly newscasts, there is no scientific reason to think that we humans are on an inevitable genetic trajectory towards idiocy.

{ Cell | Continue reading }

Customers buy a saliva kit online at 23andMe.com, send it in, and the company extracts their DNA from cheek cells preserved in saliva. In its labs, 23andMe then copies the DNA many times until there’s enough to be genotyped. Then, says lesbian scientist Emily Drabant, the DNA is examined for tens of thousands of genetic variants linked to various conditions and traits, and within weeks users get more than 100 reports on diseases, more than 50 reports on traits, more than 40 reports on carrier status, and more than 20 for drug response. […]

The most commonly requested test, Drabant says, is for sexual orientation, a particularly controversial area. […] The company initiated its sexual orientation project about six months ago, and researchers are hoping that tens of thousands of LGBT folks take the genetic test and fill out the accompanying survey — the information from which allows 23andMe to see patterns among, for example, gay men or transgender women. […] As soon as the company has a big enough sample, it plans to make those results public.

{ Advocate | Continue reading }

For more than 60 years, Robert Martensen’s lung cells replicated without a hitch, regulated by specialized enzymes called kinases. Much like thermostats that adjust the temperature in a room to make sure it’s not too hot or too cold, kinases make sure that the right number of new cells are created as old ones die. But sometime in his early sixties, something changed inside Martensen. One or more of the genes coding for his kinases mutated, causing his lung cells to begin replicating out of control.

At first the clusters of rogue cells were so small that Martensen had no idea they existed. Nor was anyone looking for them inside the lean, ruddy-faced physician, who exercised most days and was an energetic presence as the chief historian at the National Institutes of Health. Then came a day in February 2011 when Martensen noticed a telltale node in his neck while taking a shower. “I felt no pain,” he recalls, “but I knew what it was. I told myself in the shower that this was cancer—and that from that moment on, my life would be different.”

Martensen initially thought it was lymphoma, cancer of the lymph glands, which has a higher survival rate than many other cancers. But after a biopsy, he was stunned to discover he had late-stage lung cancer, a disease that kills 85 percent of patients within a year. Most survive just a few months. […]

He heard about a new drug being tested at Massachusetts General Hospital in Boston. Developed by pharmaceutical giant Pfizer, the drug had dramatically reduced lung cancer tumors and prolonged life in the couple hundred patients who had so far used it, with few side effects. But there was a catch. The new med, called Xalkori, worked for only 3 to 5 percent of all lung cancer patients.

{ Discover | Continue reading }

photo { Patrick Romero }

The U.S. government is surreptitiously collecting the DNA of world leaders, and is reportedly protecting that of Barack Obama. Decoded, these genetic blueprints could provide compromising information. In the not-too-distant future, they may provide something more as well—the basis for the creation of personalized bioweapons that could take down a president and leave no trace.

{ Atlantic | Continue reading }

We also inherit — through genes yet to be identified, of course — a trait known as developmental stability. This is essentially the accuracy with which the genetic blueprint is built. Developmental stability keeps the project on track. It reveals itself most obviously in physical symmetry. The two sides of our bodies and brains are constructed separately but from the same 23,000-gene blueprint. If you have high developmental stability, you’ll turn out highly symmetrical. Your feet will be the same shoe size, and the two sides of your face will be identical.

If you’re less developmentally stable, you’ll have feet up to a half-size different and a face that’s like two faces fused together.

{ NY Times | Continue reading }

photo { Jo Longhurst }

Technically, physical pain could be banished in humans and nonhumans alike. […]

From an engineering perspective, pain is unnecessary.

{ David Pearce/io9 | Continue reading }

images { 1. Richard Kalvar | 2. Ellsworth Kelly, Black and White, 1961 }

For a small group of people—perhaps just 1% to 3% of the population—sleep is a waste of time.

Natural “short sleepers,” as they’re officially known, are night owls and early birds simultaneously. They typically turn in well after midnight, then get up just a few hours later and barrel through the day without needing to take naps or load up on caffeine.

They are also energetic, outgoing, optimistic and ambitious, according to the few researchers who have studied them. The pattern sometimes starts in childhood and often runs in families. […]

Out of every 100 people who believe they only need five or six hours of sleep a night, only about five people really do, Dr. Buysse says. The rest end up chronically sleep deprived, part of the one-third of U.S. adults who get less than the recommended seven hours of sleep per night. […]

Dr. Fu was part of a research team that discovered a gene variation, hDEC2, in a pair of short sleepers in 2009. They were studying extreme early birds when they noticed that two of their subjects, a mother and daughter, got up naturally about 4 a.m. but also went to bed past midnight.

Genetic analyses spotted one gene variation common to them both. The scientists were able to replicate the gene variation in a strain of mice and found that the mice needed less sleep than usual, too.

{ WSJ | Continue reading }

photo { Diane Arbus }

Researchers at the Fred Hutchinson Cancer Research Center have found traces of male DNA in women’s brains, which seems to come from cells from a baby boy crossing the blood-brain barrier during pregnancy. This is known as microchimerism, and according to the researchers, this is the first description of male microchimerism in the female human brain.

{ Genome Engineering. | Continue reading }

Detectives tracking murderers, rapists and other criminals may be able to reconstruct their faces from a speck of blood left at the crime scene.

The significant advance in forensic investigation has been brought a step closer by scientists who believe they can produce portraits of suspects from a scrap of their DNA. The development would mean inaccurate photofits and unreliable eyewitness testimony would be consigned to history.

Researchers in the Netherlands working with photographs of individuals and MRI scans of their heads have identified genetic factors that contribute to facial appearance. […] The researchers from the Erasmus University Medical Centre in Rotterdam identified nine facial “landmarks”, including the position of the cheekbones, the distance between the eyes, and the height, width and length of the nose. By analysing the genomes of almost 10,000 individuals, they found five genes that controlled the positioning of the nine landmarks which affected their facial appearance.

{ Independent | Continue reading }

related { ‘Psychopaths’ have an impaired sense of smell }

photo { Richard Barnes, Unabomber 01, 1998 }

{ Study finds gene that predicts happiness in women }

The human genome is estimated to contain about 23 000 genes. Where do these genes come from? Well, from your parents. And their parents. And so on. But, surely, if we go back far enough, there haven’t been 23 000 genes all along? However life originated, the first DNA carrying organisms probably had significantly fewer genes. So, where did all these new genes come from? How are genes born?

Well, there are two main ways:

• Re-organization of existing genes. […]

• All new. In other words, not based on previously present genes. This is what the new study investigates.

{ The Beast, the Bard and the Bot | Continue reading }

related { The genetics of stupidity }

photo { Paolo Ventura }

Delaying fatherhood may offer survival advantages, say US scientists who have found children with older fathers and grandfathers appear to be “genetically programmed” to live longer. […]

Experts have known for some time that lifespan is linked to the length of structures known as telomeres that sit at the end of the chromosomes that house our genetic code, DNA. Generally, a shorter telomere length means a shorter life expectancy.

{ BBC | Continue reading }