Progress Daily

Dean Ornish, et al., just published a study (”Changes in prostate gene expression in men undergoing an intensive nutrition and lifestyle intervention“) showing that improved nutrition, stress management techniques, walking, and psychosocial support changed the expression of over 500 genes in men with early-stage prostate cancer.

The researchers studied gene expression in biopsies from 30 men who were diagnosed with low-risk prostate cancer. These men had decided not to undergo conventional treatments such as surgery, radiation, or chemotherapy for reasons unrelated to the study. They had early, small-volume prostate cancer with stable prostate specific antigen (PSA) levels and Gleason scores of six or less, meaning that their tumors were not aggressive.

The changes included a plant-based diet (predominant fruits, vegetables, legumes, soy products, and whole grains low in refined carbohydrates), moderate exercise (walking 30 minutes per day), stress management techniques (yoga-based stretching, breathing techniques, meditation, and guided imagery for one hour per day), and participating in a weekly one-hour support group. The diet was supplemented with soy, fish oil (three grams/day), vitamin E (100 units/day), selenium (200 mg/day), and vitamin C (2 grams/day).

After three months, the researchers repeated the biopsy and looked at changes in normal tissue within the prostate. We found that many disease-promoting genes (including those associated with cancer, heart disease, and inflammation) were down-regulated or “turned off,” whereas protective, disease-preventing genes were up-regulated or “turned on.” A set of cancer-promoting oncogenes called RAS was down-regulated. The Selectin E gene (which promotes inflammation and is elevated in breast cancer) was down-regulated. A gene called SFRP that suppresses tumor formation was up-regulated. These genes are the target of many new drugs that are being developed.

“Changing Your Lifestyle Can Change Your Genes,” by Dean Ornish M.D.

Once someone owns something, he places a higher value on it than he did when he acquired it. “The endowment effect” has been seen in hundreds of experiments, the most famous of which found that students were surprisingly reluctant to trade a coffee mug they had been given for a bar of chocolate, even though they did not prefer coffee mugs to chocolate when given a straight choice between the two.

The effect is not universally observed. Whereas coffee mugs generate an endowment effect, tokens that can be exchanged for coffee mugs do not.

Owen Jones and Sarah Brosnan suspect that, in the evolutionary past, giving things up, even when an apparently fair exchange seemed to be on offer, was just too risky. To test their theory, they have been training chimpanzees to trade (see “Law, Biology, and Property” — pdf file here).

When presented with a choice between peanut butter and frozen juice bars, 60% of the chimps preferred peanut butter to juice. However, when they were endowed with peanut butter, 80% of them chose to keep it instead of exchanging it for juice. And an opposite endowment effect was observed when the chimps were given juice.

Before they started work Jones & Brosnan predicted that the strength of the effect would vary with the evolutionary salience of the item in question. As predicted, when they tried the same experiments using bone and rope toys, no endowment effect was seen. Food is vital. Toys are not.

“The endowment effect,” The Economist

About one in 20 children have a group of symptoms that has come to be known as attention-deficit hyperactivity disorder (ADHD). About 60% of them carry those symptoms into adulthood. ADHD is believed to be genetic, and is associated with particular variants of receptor molecules for neurotransmitters (chemicals that carry messages between nerve cells) in the brain. In the case of ADHD, the neurotransmitter is often dopamine, which controls feelings of reward and pleasure. People with ADHD apparently receive positive neurological feedback for “inappropriate” behaviour.

ADHD sufferers are impulsive. They have trouble concentrating on any task unless they receive constant feedback, stimulation and reward. They tend to perform poorly in modern society and are prone to addictive and compulsive behaviour.

Dan Eisenberg speculated that such behavior may be advantageous for people who lead a peripatetic life. Since today’s sedentary city dwellers are recently descended from such people, natural selection may not have had time to purge the genes that cause it.

Eisenberg tested this by studying the Ariaal, a group of pastoral nomads who live in Kenya. The receptor Mr Eisenberg looked at was the 7R variant of a protein called DRD4, a variant is associated with novelty-seeking, food- and drug-cravings, and ADHD. (See “Dopamine receptor genetic polymorphisms and body composition in undernourished pastoralists.”)

The researchers looked for 7R in two groups of Ariaal. One was still pastoral and nomadic. The other had recently settled down. They found that about a fifth of the population of both groups had the 7R version of DRD4. However, the consequences of this were very different. Among the nomads, who wander around northern Kenya herding cattle, camels, sheep and goats, those with 7R were better nourished than those without. Among their settled relations, those with 7R were worse nourished than those without it.

This discovery fits past findings that 7R and a set of similar variants of DRD4 (the “long alleles”) are more common in migratory populations.

There remains the question of why 7R is found in only a fifth of the Ariaal population. One possibility is that its effects are beneficial only when they are not universal, and some sort of equilibrium between variants emerges.

“The misfits,” The Economist

 

Using selective breeding, researchers can make rats, bees and flies a lot better at learning. Animals that are better learners should over time come to dominate a population. Yet improved learning ability does not get selected amongst these animals in the wild. Tadeusz Kawecki may have discovered why.

Kawecki gave flies two different fruits as egg laying sites. One of these was laced with a bitter additive that could be detected only on contact. The flies were then given the same fruit but without an additive. Flies that avoided the fruit which had been bitter were deemed to have learned from their experience. Their offspring were reared and the experiment was run again.

After repeating the experiment for 30 generations, the offspring of the learned flies were compared with normal flies. Learning ability was bred into the flies, but it shortened their lives by 15%. And when flies were bread to live abnormally long lives, they learned less well than even average flies.

“Critical thinking,” The Economist

Reading the 3bn “base pairs” in human DNA — akin to letters, encoding a total of between 20,000 and 30,000 genes that are the “words” of genetics — is getting faster as companies find quicker ways to “read” entire stretches of DNA at a time, like reading a sentence in chunks rather than letter by letter.

The cost of sequencing an individual genome is thus falling exponentially — just as the cost of hard disk space or transistors on a chip did when computing took off.

The rapidly falling cost and time needed to map your DNA:

2003
$440M
13 years to map

2007
$10M
4 years

2008
$100K
4 weeks

2012
$100*
2 days

*Forecast

“Mapping the individual - cheaply,” by Charles Arthur

The tallest quarter of the US population earns 9-10% more than the shortest quarter, according to two recent studies. Nicola Persico, Andrew Postlewaite and Dan Silverman (”The Effect of Adolescent Experience on Labor Market Outcomes“) think this is because height gives adolescents self-confidence. Anne Case and Christina Paxson (”Stature and Status“), on the other hand, argue that people who grow to their full potential are smarter, on average.

“Feet, dollars and inches,” The Economist

Katherine Kinzler has demonstrated that preverbal infants as young as 5-6 months of age “prefer” their own native speakers. She found that American infants look longer at someone speaking with an American accent than someone with a French accent, and the opposite pattern occurs with French infants. And when two adults simultaneously offer a 10-month-old the same toy, the baby usually reaches for the one being given to them by the native speaker.

In the ancestral past, neighboring communities were often at war with each other, and the most reliable marker of an out-group member wasn’t what they looked like but how they sounded.

“Babies Don’t Like Foreigners,” by Jesse Bering

As human societies grow richer, people have fewer children. In most species, such an increase in available resources leads in the opposite reproductive direction. What makes the “demographic transition” even more paradoxical is that in less developed times and places, the rich do not have smaller families than the poor.

Most explanations of the demographic transition are social, and none is really satisfactory.

A study by Agnar Helgason, of deCODE Genetics, has recently provided a new explanation: that the mixing-up of people caused by the urbanisation which normally accompanies development is, itself, partly responsible — because it breaks up optimal mating patterns.

Iceland’s records since its founding by a few Vikings are so good that the antecedents of today’s inhabitants (apart from a handful of recent immigrants) are known with precision. Its medical records are also good, and most Icelanders have given genetic samples to deCode.

The study’s principal finding is that the most fecund marriages are between distant cousins. The optimum degree of outbreeding (measured in terms of the number of children and grandchildren produced) lay somewhere between cousins of the third and fourth degrees.

(”Kissing cousins, missing children,” The Economist)

Icelandic women born between 1800 and 1824 who mated with a third cousin had significantly more children and grandchildren (4.0 and 9.2, respectively) than women who hooked up with someone no closer than an eighth cousin (3.3 and 7.3). Those proportions held up among women born more than a century later when couples were, on average, having fewer children.

Despite the general pattern for reproductive success favoring close kinship, couples that were second cousins or more closely related did not have as many children.

With close inbreeding — between first cousins — there is a significant increase in the probability that both partners will share one or more detrimental recessive genes, leading to a 25 percent chance that these genes will be expressed in each pregnancy.

Mating with a relative might reduce a woman’s chance of having a miscarriage caused by immunological incompatibility between a mother and her child. Some individuals have an antigen (a protein that can launch an immune response) on the surface of their red blood cells called a rhesus factor. In some cases — typically during a second pregnancy — when a woman gets pregnant, she and her fetus may have incompatible blood cells, which could trigger the mother’s immune system to treat the fetus as a foreign intruder, causing a miscarriage. This occurrence is less probable if the parents are closely related, because their blood makeup is more likely to match.

It may be that the enhanced reproductive success at the level of third and fourth cousins (who on average would be expected to have inherited 0.8 percent to 0.2 percent of their genes from a common ancestor) represents a point of balance between the competing advantages and disadvantages of inbreeding and outbreeding.

(”When Incest Is Best,” by Nikhil Swaminathan)

Prior to Eric Turkheimer’s 2003 paper “Socioeconomic Status Modifies Heritability of IQ in Young Children,” scientists had found that genes account for most of the differences in IQ.

Turkheimer found that although the environmental impact on IQ is very small when you look at families with incomes in the moderate range, the reverse is the case when you look at very low-income families.

Impoverished families were underrepresented in most earlier studies.

Two things made Turkheimer’s project possible: the public release of a large, rich database including an unusually large number of children from families of very low socio-economic status; and advances in statistical methods that use computers to carry out huge numbers of computations very quickly.

Research like Turkheimer’s relies on the difference between fraternal twins, who are as genetically similar as any siblings, and identical twins, who share exactly the same genes.

For traits that are primarily determined by genes, identical twins will show no variation, but fraternal twins will. For traits that are determined by environment, identical twins and fraternal twins will show similar patterns of variation in the trait. For traits that reflect an interaction between genes and environment, identical twins will show somewhat less variation than fraternal twins.

Turkheimer found that for the families in the study at the very bottom of the socioeconomic scale, shared environment accounted for 60% of the variance in IQ; and the contribution of genes was close to zero. Non-shared environment, which includes factors such as gender, accounted for the remainder.

Further up the socio-economic ladder, the effects of environment rapidly declined, and genes took on an increasingly important role.

The research does not identify the specific environmental factors that contribute to the variations in IQ among impoverished children.

“New Thinking on Children, Poverty & IQ,” by Jan Richter

Dr Randy Thornhill manipulated pictures to make people’s faces appear more and less symmetrical, then asked volunteers of the opposite sex rank them for attractiveness. Symetery and attractiveness correlated. His later experiments have shown that all aspects of bodily symmetry contribute, down to the lengths of corresponding fingers, and that the assessment also applies to those of the same sex.

Perfect symmetry is hard for a developing embryo to maintain, so one that can maintain it must have good genes (and luck).

Other aspects of beauty, too, are indicators of health. Skin and hair condition are sensitive to illness and malnutrition.

Leslie Zebrowitz and Gillian Rhodes found 9 past studies on attractiveness and IQ, and subjected them to a “meta-analysis.”

The studies’ researchers had photographed people and asked them to do IQ tests, then showed the photographs to other people and asked them to rank the intelligence of the first lot. The results suggested that people get such judgments right often enough to be significant.

Dr Daniel Hamermesh presided over a series of surveys in the USA and Canada that showed that when all other things are taken into account, ugly people earn less than average incomes, while beautiful people earn more than the average. The ugliness “penalty” for men was -9% while the beauty premium was +5%. For women, the ugliness penalty was -6% while the beauty premium was +4%.

He found the figures for men in Shanghai are –25% and +3%; for women they are –31% and +10%. In Britain, ugly men do worse than ugly women (-18% as against -11%) but the beauty premium is the same for both (+1%).

Dr Hamermesh found that those members of a particular (anonymous) US law school rated attractive on the basis of their graduation photographs went on to earn higher salaries. Moreover, lawyers in private practice tended to be better looking than those working in government departments.

Hamermesh’s study of Dutch advertising firms showed that those with the most beautiful executives had the largest size-adjusted revenues — a difference that exceeded the salary differentials of the firms in question. Finally, he found that attractive candidates were more successful in elections for office in the American Economic Association.

Working in Shanghai, where his research indicated the difference between the ugliness penalty and the beauty bonus was greatest, Dr Hamermesh looked at how women’s spending on their cosmetics and clothes affected their income.

The beauty premium generated by such primping was worth only about 15% of the money expended.

Niclas Berggren’s research team looked at almost 2,000 candidates in Finnish elections. They asked foreigners (mainly Americans and Swedes) to examine the candidates’ campaign photographs and rank them for beauty. The more beautiful candidates, as ranked by people who knew nothing of Finland’s internal politics, tended to have been the more successful — the effect was larger for women than for men.

“To those that have, shall be given,” The Economist