2014-soraya-de-chadarevian-et-al-special-section-on-heredity-and-the-study-of-human-populations-after-1945

2014 | Soraya de Chadarevian, et.al – Special Section on “Heredity and The Study of Human Populations After 1945″

ISG professor, Soraya de Chadarevian, recently co-edited  “Heredity and The Study of Human Populations After 1945” in the Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences.

Abstract:
The essays in this issue look at the contested history of human heredity after 1945 from a new analytical angle, that of populations and the ways in which they were constructed and studied. One consequence of this approach is that we do not limit our attention to the disciplinary study of genetics. After the Second World War, populations became a central topic for an array of fields, including demography, anthropology, epidemiology, and public health. Human heredity had a role in all of these: demographers carried out mental surveys in efforts to distinguish hereditary from environmental factors, doctors screened newborns and tested pregnant women for chromosome disorders; anthropologists collected blood from remote locations to gain insights into the evolutionary history of human populations; geneticists monitored people exposed to radiation. Through this work, populations were labelled as clinical, normal, primitive, pure, vulnerable or exotic. We ask: how were populations chosen, who qualified as members, and how was the study of human heredity shaped by technical, institutional and geopolitical conditions? By following the practical and conceptual work to define populations as objects of research, the essays trace the circulation of practices across different fields and contexts, bringing into view new actors, institutions, and geographies. By doing so the collection shows how human heredity research was linked to the broader politics of the postwar world, one profoundly conditioned by Cold War tensions, by nationalist concerns, by colonial and post-colonial struggles, by modernisation projects and by a new internationalism.

2014 | Soraya de Chadarevian – Chromosome Surveys of Human Populations: Between Epidemiology and Anthropology

ISG professor, Soraya de Chadarevian, recently published “Chromosome Surveys of Human Populations: Between Epidemiology and Anthropology” in the Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences.

Abstract:
It is commonly held that after 1945 human genetics turned medical and focussed on the individual rather than on the study of human populations that had become discredited. However, a closer look at the research practices at the time quickly reveals that human population studies, using old and new tools, prospered in this period. The essay focuses on the rise of chromosome analysis as a new tool for the study of human populations. It reviews a broad array of population studies ranging from newborn screening programmes to studies of isolated or ‘primitive’ people. Throughout, it highlights the continuing role of concerns and opportunities raised by the propagation of atomic energy for civilian and military uses, the collection of large data bases and computers, and the role of international organisations like the World Health Organisation and the International Biological Programme in shaping research agendas and carving out a space for human heredity in the postwar era.

N.Y. Times, AirTalk Explore Hormones’ Impact in Sports

Dr. Eric Vilain, a professor of human genetics, urology and pediatrics at the David Geffen School of Medicine at UCLA and co-director of UCLA’s Institute for Society and Genetics, was interviewed Oct. 6 by the New York Times and Oct. 7 by KPCC 89.3FM’s AirTalk show about a young female sprinter from India who was banned from competition due to her unusually high levels of testosterone. The NYT article was syndicated by the Times of India.

Texas A&M Biologists Unlock Non-Coding Half of Human Genome with Novel DNA Sequencing Technique

An obscure swatch of human DNA once thought to be nothing more than biological trash may actually offer a treasure trove of insight into complex genetic-related diseases such as cancer and diabetes, thanks to a novel sequencing technique developed by biologists at Texas A&M University. The game-changing discovery was part of a study led by Texas A&M biology doctoral candidate John C. Aldrich and Dr. Keith A. Maggert, an associate professor in the Department of Biology, to measure variation in heterochromatin. This mysterious, tightly packed section of the vast, non-coding section of the human genome, widely dismissed by geneticists as “junk,” previously was thought by scientists to have no discernable function at all.

Aldrich’s findings, published today in the online edition of the journal PLOS ONE, showed that differences in the heterochromatin exist, confirming that the junk DNA is not stagnant as researchers originally had believed and that mutations which could affect other parts of the genome are capable of occurring. “We know that there is hidden variation there, like disease proclivities or things that are evolutionarily important, but we never knew how to study it,” Maggert said. “We couldn’t even do the simplest things because we didn’t know if there was a little DNA or a lot of it. “This work opens up the other non-coding half of the genome.”

The uncharted genome sequences have been a point of contention in scientific circles for more than a decade, according to Maggert, a Texas A&M faculty member since 2004. It had long been believed that the human genome — the blueprint for humanity, individually and as a whole — would be packed with complex genes with the potential to answer some of the most pressing questions in medical biology.

Read the full article here.

Study Shows How Epigenetic Memory is Passed Across Generations

A growing body of evidence suggests that environmental stresses can cause changes in gene expression that are transmitted from parents to their offspring, making “epigenetics” a hot topic. Epigenetic modifications do not affect the DNA sequence of genes, but change how the DNA is packaged and how genes are expressed. Now, a study by scientists at UC Santa Cruz shows how epigenetic memory can be passed across generations and from cell to cell during development.

The study, published September 19 in Science, focused on one well studied epigenetic modification–the methylation of a DNA packaging protein called histone H3. Methylation of a particular amino acid (lysine 27) in histone H3 is known to turn off or “repress” genes, and this epigenetic mark is found in all multicellular animals, from humans to the tiny roundworm C. elegans that was used in this study. ”There has been ongoing debate about whether the methylation mark can be passed on through cell divisions and across generations, and we’ve now shown that it is,” said corresponding author Susan Strome, a professor of molecular, cell and developmental biology at UC Santa Cruz.

Strome noted that the findings in this study of transmission of histone methylation in C. elegans have important implications in other organisms, even though different organisms use the repressive marker that was studied to regulate different genes during different aspects of development. All animals use the same enzyme to create the same methylation mark as a signal for gene repression, and her colleagues who study epigenetics in mice and humans are excited about the new findings, Strome said.

Read the full article here.

Why Do Chimps Kill Each Other?

War—what is it good for? “Absolutely nothing” according to the refrain of a 1970 hit song. Many humans would agree with this sentiment. But a major new study of warfare in chimpanzees finds that lethal aggression can be evolutionarily beneficial in that species, rewarding the winners with food, mates, and the opportunity to pass along their genes. The findings run contrary to recent claims that chimps fight only if they are stressed by the impact of nearby human activity—and could help explain the origins of human conflict as well.

Ever since primatologist Jane Goodall’s pioneering work at Gombe Stream National Park in Tanzania in the 1970s, researchers have been aware that male chimps often organize themselves into warring gangs that raid each other’s territory, sometimes leaving mutilated dead bodies on the battlefield. Primatologists have concluded that their territorial battles are evolutionarily adaptive. But some anthropologists have resisted this interpretation, insisting instead that today’s chimps are aggressive only because they are endangered by human impact on their natural environment. For example, when humans cut down forests for farming or other uses, the loss of habitat forces chimps to live in close proximity to one another and to other groups. Feeding chimps can also increase their population density by causing them to cluster around human camps, thus causing more competition between them.

The researchers created a series of computer models to test whether the observed killings could be better explained by adaptive strategies or human impacts. The models incorporated variables such as whether the animals had been fed by humans, the size of their territory (smaller territories presumably corresponding to greater human encroachment), and other indicators of human disturbance, all of which were assumed to be related to human impacts; and variables such as the geographic location of the animals, the number of adult males, and the population density of the animals, which the team considered more likely to be related to adaptive strategies.

“The contrast could not be more stark” between how the two hypotheses fared, says William McGrew, a primatologist at the University of Cambridge in the United Kingdom, who praises the study as a “monumental collaborative effort.” Joan Silk, an anthropologist at Arizona State University, Tempe, agrees. The study “weighs competing hypotheses systematically,” she says. “Advocates of the human impact hypothesis … must challenge [the study’s] empirical findings, or modify their position.”

Read the full article here.

How Evolutionary Principles Could Help Save Our World

The age of the Anthropocene–the scientific name given to our current geologic age–is dominated by human impacts on our environment. A warming climate. Increased resistance of pathogens and pests. A swelling population. Coping with these modern global challenges requires application of what one might call a more-ancient principle: evolution. That’s the recommendation of a diverse group of researchers, in a paper published today in the online version of the journal Science. A majority of the nine authors on the paper have received funding from the National Science Foundation (NSF).

“Evolution isn’t just about the past anymore, it’s about the present and the future,” said Scott Carroll, an evolutionary ecologist at University of California-Davis and one of the paper’s authors. Addressing societal challenges–food security, emerging diseases, biodiversity loss–in a sustainable way is “going to require evolutionary thinking.” The paper reviews current uses of evolutionary biology and recommends specific ways the field can contribute to the international sustainable development goals (SDGs), now in development by the United Nations.

Their recommendations include gene therapies to treat disease, choosing drought-and-flood-resistant crop varieties and altering conservation strategies to protect land with high levels of genetic diversity. Evolutionary biologists don’t have all the answers, said Smith. And using applied evolution is not without risk. But we have reached a point “where we need to take risks in many cases,” he said. “We can’t just sit back and be overly conservative, or we’re going to lose the game.”

Read the full article here.

Why Humans Don’t Suffer From Chimpanzee Malaria: DNA Region Controlling Red Blood Cell Invasion Holds Genetic Key to Infection

By comparing the genomes of malaria parasites that affect chimpanzees and those that affect humans, researchers discovered that it is the difference in the parasites’ surface proteins that determine which host it will infect.

Out of a genome of approximately 5,500 genes, researchers found that most genes have directly equivalent counterparts between the human and primate parasites. However, portions of the P. falciparum genome that differed most profoundly from the P. reichenowi parasite that infects chimpanzees were found to encode proteins that help the parasite to bind to and invade red blood cells, which is where the parasite grows and multiplies. “Discovering that the key differences lie in genes responsible for red blood cell invasion reassures us that we’ve been looking in the right place,” says Dr Thomas Otto, first author at the Wellcome Trust Sanger Institute. “Researchers have identified surface proteins as promising vaccine candidates already; and our finding adds more support, showing that it is the difference in the parasites’ surface proteins that determine which host it will infect.”

This is the first time that an essentially complete genome has been produced for a malaria parasite that infects such a close relative of humans. It provides the first systematic view of the differences between parasites that infect humans and those that infect our close relatives. Human malaria emerged from the Great Apes, so this comparison using chimpanzee malaria is the closest that scientists have come to a full catalogue of the changes associated with parasites switching from our primate relatives into humans.

Read the full article here.