Recent Tibetan adaptation for high altitude

From the New Scientist:

Mountain-dwelling Tibetans have genetically adapted to life at altitude in the past 3000 years – the fastest genetic change known to have occurred in humans.

Rasmus Nielsen at the University of California, Berkeley, and his colleagues looked at the DNA of people living in two villages at 4300 and 4600 metres above sea level in Tibet. At these heights, oxygen levels are about 40 per cent lower than at sea level and lowlanders experience hypoxia, which is associated with headaches, fatigue, smaller fetuses and more deaths in infancy.

Tibetans don't suffer from hypoxia, but it has been unclear why. Nielsen's team compared the DNA of 50 Tibetans with that of 40 Han Chinese people from Beijing and 200 people of European ancestry from Denmark, all of whom live at altitudes below 2000 metres.

By comparing the DNA of the three groups, the team identified the specific genetic differences between the Tibetan and Han populations, thought to have diverged around 2750 years ago.

Science Vol. 329. no. 5987, pp. 72 - 75
DOI: 10.1126/science.1189406

Genetic Evidence for High-Altitude Adaptation in Tibet

Tatum S. Simonson et al.

Abstract

Tibetans have lived at very high altitudes for thousands of years, and they have a distinctive suite of physiological traits that enable them to tolerate environmental hypoxia. These phenotypes are clearly the result of adaptation to this environment, but their genetic basis remains unknown. We report genome-wide scans that reveal positive selection in several regions that contain genes whose products are likely involved in high-altitude adaptation. Positively selected haplotypes of EGLN1 and PPARA were significantly associated with the decreased hemoglobin phenotype that is unique to this highland population. Identification of these genes provides support for previously hypothesized mechanisms of high-altitude adaptation and illuminates the complexity of hypoxia-response pathways in humans.

Link
Science Vol. 329. no. 5987, pp. 75 - 78
DOI: 10.1126/science.1190371

Sequencing of 50 Human Exomes Reveals Adaptation to High Altitude

Xin Yi et al.

Abstract

Residents of the Tibetan Plateau show heritable adaptations to extreme altitude. We sequenced 50 exomes of ethnic Tibetans, encompassing coding sequences of 92% of human genes, with an average coverage of 18x per individual. Genes showing population-specific allele frequency changes, which represent strong candidates for altitude adaptation, were identified. The strongest signal of natural selection came from endothelial Per-Arnt-Sim (PAS) domain protein 1 (EPAS1), a transcription factor involved in response to hypoxia. One single-nucleotide polymorphism (SNP) at EPAS1 shows a 78% frequency difference between Tibetan and Han samples, representing the fastest allele frequency change observed at any human gene to date. This SNP’s association with erythrocyte abundance supports the role of EPAS1 in adaptation to hypoxia. Thus, a population genomic survey has revealed a functionally important locus in genetic adaptation to high altitude.

Link

Preference for masculine/feminine-looking men and national health

Supplementary Table 1 has the relevant data. I have sorted the data on national health index, and average masculinity preference.



Note that country scores were limited only to those judges who identified themselves as White.

Some observations:

• As the authors note health index is related inversely with preference for masculinity. However, there are some interesting cases:
• Canada and the USA have similar (high) masculinity preferences, even though they differ substantially in the health index.
• Iceland and Norway (small sample sizes, but we can combine the two) have a good health index as does Sweden, but a much stronger preference than masculinity than Sweden.
• The vast majority of EU nations are around ~0.4 in the masculinity preference index.

An untested factor is variation in the levels of facial masculinity across different nations. Differences in preference may not reflect differences in health, but rather differences in average facially-expressed masculinity. It would be interesting to use anthropometric data to test this possible influence, as "White" populations from different nations are not anthropometrically equivalent.

Another untested factor is the racial makeup of different nations. It is fairly striking that the top nations in masculinity preference (we can exclude Bulgaria with its small sample) are all the ones with the longest histories of racial co-existence. This may have altered attractiveness standards in these countries, as the Caucasoids within each country may have altered perceptions of attractiveness due either to familiarization with other races or (conversely) due to a desire to distance themselves from them phenotypically.

PS: You can download the paper and other face-related research at the Facelab.

Proceedings of the Royal Society B doi:10.1098/rspb.2009.2184

The health of a nation predicts their mate preferences: cross-cultural variation in women's preferences for masculinized male faces

Lisa M. DeBruine et al.

Abstract

Recent formulations of sexual selection theory emphasize how mate choice can be affected by environmental factors, such as predation risk and resource quality. Women vary greatly in the extent to which they prefer male masculinity and this variation is hypothesized to reflect differences in how women resolve the trade-off between the costs (e.g. low investment) and benefits (e.g. healthy offspring) associated with choosing a masculine partner. A strong prediction of this trade-off theory is that women's masculinity preferences will be stronger in cultures where poor health is particularly harmful to survival. We investigated the relationship between women's preferences for male facial masculinity and a health index derived from World Health Organization statistics for mortality rates, life expectancies and the impact of communicable disease. Across 30 countries, masculinity preference increased as health decreased. This relationship was independent of cross-cultural differences in wealth or women's mating strategies. These findings show non-arbitrary cross-cultural differences in facial attractiveness judgements and demonstrate the use of trade-off theory for investigating cross-cultural variation in women's mate preferences.

Link

Eminence, IQ, physical and mental health

The negative relationship between physical health and IQ is the most noteworthy finding, as it goes against the observation of IQ being associated with good health. To explain this, the authors propose either that "the course that leads from initial talent to extraordinary achievement may require pathways of intellectual and social development that diverge radically from normal personal growth," or "Excessive selection can truncate the variable variances so that correlations are reduced to zero. [...] As an example, among students accepted to graduate school in psychology, the undergraduate grade point average can be negatively correlated with scores received on the Graduate Record Examination (Dawes, 1975)."

From the paper:

Relative to the average, IQ was higher among the philosophers and imaginative writers, but lower among the commanders, composers, and artists.

...

commanders, enjoyed a level of early physical health substantially above the average. [...] Second, one domain stands out as being the lowest in mental
health: the imaginative writers.

Psychological Science doi:10.1111/j.1467-9280.2009.02313.x

Eminence, IQ, Physical and Mental Health, and Achievement Domain: Cox's 282 Geniuses Revisited

Dean Keith Simonton and Anna V. Song

Abstract

Catharine Cox published two studies of highly eminent creators and leaders, the first in 1926 as the second volume of Terman's landmark Genetic Studies of Genius and the second in 1936 as a coauthored article. The former publication concentrated on the relation between IQ and achieved eminence, and the latter focused on early physical and mental health. Taking advantage of unpublished data from the second study, we examined, for the first time, the relationships among achieved eminence, IQ, early physical and mental health, and achievement domain. The correlation and regression analyses showed, for these 282 individuals, that eminence is a positive function of IQ and that IQ is a positive function of mental health and a negative function of physical health, implying an indirect effect of physical and mental health on eminence. Furthermore, levels of early physical and mental health vary across 10 specific domains of achievement.

Link

Female bosses cause distress to female (but not male) employees

This paper shows that women with a female supervisor or female/male supervisors suffer distress and ill health. Men, on the other hand fare best when they have a female/male supervisor team. Feel free to post your own horror stories from the workplace.

Journal of Health and Social Behavior, Volume 49, Number 3, September 2008 , pp. 286-300(15)

Relational Demography in the Workplace and Health: An Analysis of Gender and the Subordinate-Superordinate Role-Set

Schieman, Scott; McMullen, Taralyn

Abstract

Using data from a 2005 national survey of working adults in the United States, we examine the effects of the gender composition of the superordinate-subordinate role-set on mental and physical health measures. Subordinates' and superordinates' genders are important determinants. Men who work in gender-mixed superordinate contexts (i.e., with one male and one female superior) report lower levels of distress and physical symptoms than men who work with one male superior. Women who work with one male superior report less distress and fewer physical symptoms compared to women who work with one female superior or in gender-mixed superordinate contexts. With a few exceptions, these observations generally hold net of occupation, job sector, and an array of work-related conditions. We discuss the implications of these findings in light of predictions derived from the similarity-attraction and role congruity theories. We also outline ways that theoretical development in relational demography can be refined by a more specific focus on the demographic characteristics—especially gender—of the superordinate-subordinate role-set.

Link

Overweight and obesity in young Greek men

Obes Rev. 2007 Oct 24; [Epub ahead of print]

Prevalence of overweight and obesity in young Greek men.

Papadimitriou A, Fytanidis G, Papadimitriou DT, Priftis KN, Nicolaidou P, Fretzayas A.

We determined the prevalence of overweight and obesity in young Greek men in 2006 and examined variations related to their place of residence and educational level. Body height and weight were measured in 2568 conscripts of the Greek army, aged 19-26 years. The calculated body mass index (BMI, kg m(-2)) was correlated to their socio-demographic characteristics, i.e. level of education and place of residence (urban or rural). Overweight and obesity were defined according to the World Health Organization classification. Mean BMI (standard deviation) of the conscripts was 24.7 (4.2). The prevalence of overweight (30 > BMI >/= 25 kg m(-2)) was 28.5% and correlated positively with a higher educational level, whereas the prevalence of obesity (BMI >/= 30 kg m(-2)) was 10.4% and correlated positively with a lower educational level. Our data were compared with those of similar studies performed in the years 1969: BMI 23.8 (1.4) (P < 0.0001) and 1990: BMI 23.8 (2.9) (P < 0.0001), showing a positive secular trend for BMI in Greek conscripts in the last 16 years. In conclusion, we documented an alarmingly high prevalence of overweight and obesity among young Greek men.

Link

Health status of Greek centenarians

Arch Gerontol Geriatr. 2007 May 16; [Epub ahead of print]

Assessment of the health status of Greek centenarians.

Darviri C, Demakakos P, Charizani F, Tigani X, Tsiou C, Chalamandaris AG, Tsagkari C, Chliaoutakis J.

The present study aims at describing the health status of a sample of relatively functional and healthy Greek centenarians and at exploring the potential gender differences in health in this sample. Its objectives are to add to the accumulation of knowledge about the health status of centenarians and therefore to contribute to the exploration of the mechanisms of healthy longevity. The study employs a non-representative community sample of Greek centenarians of both sexes (N=47). It uses descriptive statistics in order to outline the health status of the participants and non-parametric tests to assess the statistical significance of the observed sex-differences. The study shows that the centenarians of our sample are relatively healthy and functional (15% of the sample was free of any major chronic disease). It also suggests, that the sex-difference in survival is statistical significant (p less or equal 0.013), and that the morbidity and co-morbidity rates of the Greek centenarians are relatively low (mean value of co-morbidity=1.4+/-0.97, S.D.). Moreover, it provides valuable information on the anthropometric characteristics of the sample, and on health services utilization. These results indicate that exceptional longevity is not necessarily accompanied by disability, disease and total dependence on others.

Link

Binge-drinking in the European Union

The full report has more data.

Mediterranean diet in Greco-Roman and Byzantine writers

Obes Surg. 2007 Jan;17(1):112-6.

Greco-Roman and Byzantine views on obesity.

Papavramidou N, Christopoulou-Aletra H.

This paper focuses on the Greco-Roman views on obesity with certain extensions to the Byzantine era. The writers reported hereby are Aulus Cornelius Celsus (circa 25 BC), Dioscorides Pedanius (40-90 AD), Soranus of Ephesus (98-138 AD) whose writings on the subject survived through Caelius Aurelianus (5th c. AD), Claudius Aelianus (3rd C. AD), Oribasius (324-400 AD), Aetius of Amida (circa 450 AD), Alexander Trallianus (6th c. AD), Paulus Aegineta (7th c. AD), and Theophilus Protospatharius (9th C. AD). All of the authors treat the subject of etiology, clinical manifestations and treatment, while the Hippocratic and Galenic views seem to be taken into consideration. The most important observation made on the basis of the studied texts is the emersion of the notion of the "Mediterranean diet" that was advised as an extremely successful conservative way to treat obesity. The Greco-Roman and Byzantine writers continue the long tradition of treating obesity and set the foundations for modern methods of treatment.

Link

Mycobacterium bovis in Iron Age Siberian

Microbiology. 2007 Apr;153(Pt 4):1243-9.

First report of Mycobacterium bovis DNA in human remains from the Iron Age.

Taylor GM, Murphy E, Hopkins R, Rutland P, Chistov Y.

Tuberculosis has plagued humankind since prehistoric times, as is evident from characteristic lesions on human skeletons dating back to the Neolithic period. The disease in man is due predominantly to infection with either Mycobacterium tuberculosis or Mycobacterium bovis, both members of the M. tuberculosis (MTB) complex. A number of studies have shown that when conditions permit, surviving mycobacterial DNA may be amplified from bone by PCR. Such ancient DNA (aDNA) analyses are subject to stringent tests of authenticity and, when feasible, are invariably limited by DNA fragmentation. Using PCRs based on single-nucleotide polymorphic loci and regions of difference (RDs) in the MTB complex, a study was made of five Iron Age individuals with spinal lesions recovered from the cemetery of Aymyrlyg, South Siberia. A sensitive screening PCR for MTB complex mycobacteria was positive in four out of the five cases. Genotyping evidence indicated that all four cases were due to infection with M. bovis rather than M. tuberculosis and the data were consistent with the proposed phylogenetic model of the MTB complex. This is believed to be the first report of M. bovis causing Pott's disease in archaeological human remains. The study shows that genotyping of ancestral strains of MTB complex mycobacteria from contexts of known date provides information which allows the phylogeny of the model to be tested. Moreover, it shows that loss of DNA from RD4, which defines classic M. bovis, had already occurred from the genome over 2000 years before the present.

Link

Admixture and disease in African Americans

Human Genetics (online early)

Genetic ancestry, population sub-structure, and cardiovascular disease-related traits among African-American participants in the CARDIA Study

Alexander P. Reiner et al.

Abstract African-American populations are genetically admixed. Studies performed among unrelated individuals from ethnically admixed populations may be both vulnerable to confounding by population stratification, but offer an opportunity for efficiently mapping complex traits through admixture linkage disequilibrium. By typing 42 ancestry-informative markers and estimating genetic ancestry, we assessed genetic admixture and heterogeneity among African-American participants in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. We also assessed associations between individual genetic ancestry and several quantitative and binary traits related to cardiovascular risk. We found evidence of population sub-structure and excess inter-marker linkage disequilibrium, consistent with recent admixture. The estimated group admixture proportions were 78.1% African and 22.9% European, but differed according to geographic region. In multiple regression models, African ancestry was significantly associated with decreased total cholesterol, decreased LDL-cholesterol, and decreased triglycerides, and also with increased risk of insulin resistance. These observed associations between African ancestry and several lipid traits are consistent with the general tendency of individuals of African descent to have healthier lipid profiles compared to European-Americans. There was no association between genetic ancestry and hypertension, BMI, waist circumference, CRP level, or coronary artery calcification. These results demonstrate the potential for confounding of genetic associations with some cardiovascular disease-related traits in large studies involving US African-Americans.

Link

The Evolution of adult height in Europe

From the paper:

From the evidence in Figure 3 and Figure 4 we can conclude for the Southern European countries that Greeks are the tallest for both males and females and Portuguese are the shortest ones in both cases. Both countries show a similar evolution profile in the period under consideration. At contrast, Spanish males and females for the last cohorts are growing more significantly than those in the other Southern European countries.

Economics & Human Biology In Press, Accepted Manuscript, Available online 1 March 2007,

The Evolution of Adult Height in Europe: A Brief Note

Jaume Garcia

Abstract

This paper presents new evidence on the evolution of adult height in 10 European countries for cohorts born between 1950 and 1980 using the European Community Household Panel (ECHP), which collects height data from Austria, Belgium, Denmark, Finland, Greece, Ireland, Italy, Portugal, Spain and Sweden. Our findings show a gradual increase in adult height across all countries. However, countries from Southern Europe (Greece, Italy, Portugal, and Spain) experienced greater gains in stature than those located in Northern Europe (Austria, Belgium, Denmark, Finland, Ireland, and Sweden).

Early Europeans unable to digest milk

This is the EurekAlert release; I did not see the PNAS article online yet.

The first direct evidence that early Europeans were unable to digest milk has been found by scientists at UCL (University College London) and Mainz University.

In a study, published in the journal 'PNAS', the team shows that the gene that controls our ability to digest milk was missing from Neolithic skeletons dating to between 5840 and 5000 BC. However, through exposure to milk, lactose tolerance evolved extremely rapidly, in evolutionary terms. Today, it is present in over ninety per cent of the population of northern Europe and is also found in some African and Middle Eastern populations but is missing from the majority of the adult population globally.

Dr Mark Thomas, UCL Biology, said: "The ability to drink milk is the most advantageous trait that's evolved in Europeans in the recent past. Without the enzyme lactase, drinking milk in adulthood causes bloating and diarrhoea. Although the benefits of milk tolerance are not fully understood yet, they probably include: the continuous supply of milk compared to the boom and bust of seasonal crops; its nourishing qualities; and the fact that it's uncontaminated by parasites, unlike stream water, making it a safer drink. All in all, the ability to drink milk gave some early Europeans a big survival advantage."

The team carried out DNA tests on Neolithic skeletons from some of the earliest organised farming communities in Europe. Their aim was to find out whether these early Europeans from various sites in central, northeast and southeast Europe, carried a version of the lactase gene that controls our ability to produce the essential enzyme lactase into adulthood. The team found that it was absent from their ancient bone DNA. This led the researchers to conclude that the consumption and tolerance of milk would have been very rare or absent at the time.

Scientists have known for decades that at some point in the past all humans were lactose intolerant. What was not known was just how recently lactose tolerance evolved.

Dr Thomas said: "To go from lactose tolerance being rare or absent seven to eight thousand years ago to the commonality we see today in central and northern Europeans just cannot be explained by anything except strong natural selection. Our study confirms that the variant of the lactase gene appeared very recently in evolutionary terms and that it became common because it gave its carriers a massive survival advantage. Scientists have inferred this already through analysis of genes in today's population but we've confirmed it by going back and looking at ancient DNA."

This study challenges the theory that certain groups of Europeans were lactose tolerant and that this inborn ability led the community to pursue dairy farming. Instead, they actually evolved their tolerance of milk within the last 8000 years due to exposure to milk.

Dr Thomas said: "There were two theories out there: one that lactose tolerance led to dairy farming and another that exposure to milk led to the evolution of lactose tolerance. This is a simple chicken or egg question but one that is very important to archaeologists, anthropologists and evolutionary biologists. We found that the lactose tolerance variant of the lactase gene only became common after dairy farming, which started around 9 thousand years ago in Europe.

"This is just one part of the picture researchers are gathering about lactose tolerance and the origins of Europeans. Next on the list is why there is such disparity in lactose tolerance between populations. It's striking, for example, that today around eighty per cent of southern Europeans cannot tolerate lactose even though the first dairy farmers in Europe probably lived in those areas. Through computer simulations and DNA testing we are beginning to get glimpses of the bigger early European picture."

UPDATE: abstract (1 March)

Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0607187104

bsence of the lactase-persistence-associated allele in early Neolithic Europeans

J. Burger et al.

Lactase persistence (LP), the dominant Mendelian trait conferring the ability to digest the milk sugar lactose in adults, has risen to high frequency in central and northern Europeans in the last 20,000 years. This trait is likely to have conferred a selective advantage in individuals who consume appreciable amounts of unfermented milk. Some have argued for the "culture-historical hypothesis," whereby LP alleles were rare until the advent of dairying early in the Neolithic but then rose rapidly in frequency under natural selection. Others favor the "reverse cause hypothesis," whereby dairying was adopted in populations with preadaptive high LP allele frequencies. Analysis based on the conservation of lactase gene haplotypes indicates a recent origin and high selection coefficients for LP, although it has not been possible to say whether early Neolithic European populations were lactase persistent at appreciable frequencies. We developed a stepwise strategy for obtaining reliable nuclear ancient DNA from ancient skeletons, based on (i) the selection of skeletons from archaeological sites that showed excellent biomolecular preservation, (ii) obtaining highly reproducible human mitochondrial DNA sequences, and (iii) reliable short tandem repeat (STR) genotypes from the same specimens. By applying this experimental strategy, we have obtained high-confidence LP-associated genotypes from eight Neolithic and one Mesolithic human remains, using a range of strict criteria for ancient DNA work. We did not observe the allele most commonly associated with LP in Europeans, thus providing evidence for the culture-historical hypothesis, and indicating that LP was rare in early European farmers.

Link

Fitness has fallen since the days of Ancient Greece (?)

I think that a more likely explanation may be that our modern reconstructions of a trireme as well as the way the ship is used are not really as good as they can be. It should be remembered that the trireme reconstruction is based primarily on literary and artistic evidence and a lot of guesswork. Still, this is an interesting piece of work. Also, the ancient literary accounts giving a measure of distance/time are not really exact, and it should also be remembered that the nautical feats that were recorded were exceptional when triremes had to cover distances in a hurry, and do not represent the average performance of the ancient sailors.

Fitness Has Fallen Since The Days Of Ancient Greece

We may not be as fit as the people of ancient Athens, despite all that modern diet and training can provide, according to research by University of Leeds (UK) exercise physiologist, Dr Harry Rossiter.

Dr Rossiter measured the metabolic rates of modern athletes rowing a reconstruction of an Athenian trireme, a 37m long warship powered by 170 rowers seated in three tiers. Using portable metabolic analysers, he measured the energy consumption of a sample of the athletes powering the ship over a range of different speeds to estimate the efficiency of the human engine of the warship. The research is published in New Scientist .

By comparing these findings to classical texts that record details of their endurance, he realised that the rowers of ancient Athens -- around 500BC -- would had to have been highly elite athletes, even by modern day standards.

Says Dr Rossiter: "Ancient Athens had up to 200 triremes at any one time, and with 170 rowers in each ship, the rowers were clearly not a small elite. Yet this large group, it seems, would match up well with the best of modern athletes. Either ancient Athenians had a more efficient way of rowing the trireme or they would have to be an extremely fit group. Our data raise the interesting notion that these ancient athletes were genetically better adapted to endurance exercise than we are today."

Dr Rossiter worked closely with Professor Boris Rankov, Professor of Classics at Royal Holloway, University of London to interpret the details of the endurance of the ancient rowers from classical texts. Many of these texts were originally collected and used to estimate sustainable ship speeds in The Athenian Trireme (CUP, 2rd edition 2000), which Professor Rankov co-authored.

For example, one account talks of the Athenians quelling a revolt in Mytilene on the island of Lesbos in the eastern Aegean. The Athenian assembly ordered all Mytiline's men to death, and despatched a trireme to carry out this command. The next day, the assembly relented and sent a second trireme to halt the massacre. According to the records of Thucydides, this second trireme would have made the journey in about 24 hours, rowing in shifts and eating while they rowed, so the ship could travel non-stop.

Says Dr Rossiter: "From these details we can estimate the average sustainable ship speeds. Then, using the reconstruction we measured the metabolic demands of the human engine required to sustain these speeds. If the historians are correct, we would struggle to find enough people at that level of fitness today to power the ships at those speeds."

Triremes were a huge technological advance, allowing Athens to dominate the seas. They had a strong keel, taken forward into a huge spike covered in bronze plates, which meant they could ram and hole enemy ships -- a new technique in naval warfare. To ensure sufficient impact to cause damage, the triremes had to reach great speeds -- so were designed with more than three times more rowers than earlier warships. By placing the rowers on three tiers, the ship could remain a manoeuvrable length and weight.

The trireme used in Dr Rossiter's research, Olympias, was built in the 1980s and was used to carry the Olympic flame to Piraeus, the port near Athens, at the start of the last Olympic Games. It is now housed in a museum in Piraeus.

An overview of child well-being in rich countries

The full report is here.

Mismatch: Why Our World No Longer Fits Our Bodies

A new book which proposes that human health and lifespan will deteriorate because our bodies are no longer adapted in the increasingly foreign environment in which we find ourselves. I think that there is a three-way race between evolution, cultural change, and medical science. We may very well have sub-optimal genes for our modern environments, and evolution may not be able to catch up with the rates of cultural change, but medical science -by default- allows human beings to counterbalance our natural shortcomings. Until today, it has seemed to won the race, as increasing human lifespans indicate, but perhaps not into the future.

Here is a Guardian article on the book. An excerpt from the publisher:

We have built a world that no longer fits our bodies. Our genes - selected through our evolution - and the many processes by which our development is tuned within the womb, limit our capacity to adapt to the modern urban lifestyle. There is a mismatch. We are seeing the impact of this mismatch in the explosion of diabetes, heart disease and obesity. But it also has consequences in earlier puberty and old age.

Bringing together the latest scientific research in evolutionary biology, development, medicine, anthropology and ecology, Peter Gluckman and Mark Hanson, both leading medical scientists, argue that many of our problems as modern-day humans can be understood in terms of this fundamental and growing mismatch. It is an insight that we ignore at our peril.

Increase of weight in Greek schoolchildren in 20th century

Med Sci Monit. 2006 Dec 18;13(1):RA8-11 [Epub ahead of print]

The secular trend of body weight of Greek schoolchildren in the 20(th) century.

Papadimitriou A, Douros K, Fretzayas A, Nicolaidou P.

Background: Improvements in socioeconomic conditions in the 20(th) century had a dramatic impact on the growth and development of children, resulting in greater somatic growth and earlier pubertal maturation. Furthermore, in the last part of that century childhood obesity took on epidemic proportions in many countries The aim of the study was to present the secular trend of body weight of Greek schoolchildren in the 20(th) century. Material/Methods: The data were taken from growth studies the authors conducted themselves or were able to find in the Greek literature. All studies were cross-sectional and spanned the years from 1920 to 1995. The studies referred mainly to children living in Athens or other major cities of the country. Results: The data were taken from growth studies the authors conducted themselves or were able to find in the Greek literature. All studies were cross-sectional and spanned the years from 1920 to 1995. The studies referred mainly to children living in Athens or other major cities of the country. Conclusions: Improvement in the socioeconomic conditions in Greece resulted in an increase in body weight in Greek schoolchildren in the 20(th) century. However, this increase tended to stop in adolescent girls.

Link

Haplogroups H and U and Alzheimer's

Cell Mol Neurobiol. 2006 Dec 21; [Epub ahead of print]

Do Haplogroups H and U Act to Increase the Penetrance of Alzheimer's Disease?

Fesahat F, Houshmand M, Panahi MS, Gharagozli K, Mirzajani F.

1. Alzheimer's disease (AD) is the most common form of dementia in the elderly in which interplay between genes and the environment is supposed to be involved. Mitochondrial DNA (mtDNA) has the only noncoding regions at the displacement loop (D-loop) region that contains two hypervariable segments (HVS-I and HVS-II) with high polymorphism. mtDNA has already been fully sequenced and many subsequent publications have shown polymorphic sites, haplogroups, and haplotypes. Haplogroups could have important implications to understand the association between mutability of the mitochondrial genome and the disease.2. To assess the relationship between mtDNA haplogroup and AD, we sequenced the mtDNA HVS-I in 30 AD patients and 100 control subjects. We could find that haplogroups H and U are significantly more abundant in AD patients (P = 0.016 for haplogroup H and P = 0.0003 for haplogroup U), Thus, these two haplogroups might act synergistically to increase the penetrance of AD disease.

Link