In the mid-20th century, the Eastern Highlands province of Papua New Guinea was plagued by a mysterious disease that left entire villages without adult women.
The Fore people at the center of the epidemic called this out: dry – word for tremors – due to which people lose control of their limbs and body functions before a tremor occurs before death.
The tribe was relatively isolated from the rest of the world until the 1930s, but as the epidemic reached its peak in the 1950s, it attracted the attention of researchers from around the world who sought to understand the disease that had eluded explanation.
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After eliminating the contaminants, the researchers suggested it might be genetic; until it was discovered that kuru was spread through the tradition of mortuary feasts, where the Fore ate the corpses of their deceased relatives.
Kuru, a type of prion disease, is a progressive neurodegenerative disease caused by a change in the shape of the body’s normal prion protein. The most likely explanation for its spread is that at some point a person died from a randomly occurring prion disease, such as the occasional Creutzfeldt-Jakob disease (CJD), and the infected tissue was subsequently consumed by society.
Women and children were most affected by the disease, as the body was ritually dismembered and eaten according to spiritual beliefs, and certain tissues went to certain relatives; because the brain and spinal cord were distributed to where prions were concentrated.
The Kuru epidemic waned over the decades after funerals were banned in the 1950s, but a research center in the United Kingdom devoted itself to studying the disease after exposure to an outbreak of prion disease.
The UK Medical Research Council’s prion unit at University College London was established in the wake of BSE (or “mad cow disease”), which broke the species barrier in 1995 and was introduced by cattle being crushed and then returned to cattle. There are young people dying from the CJD variant.
The new research, conducted by the unit and published this week in the American Journal of Human Genetics, provides the most comprehensive genetic study to date of people living in the Eastern Highlands and also explores the impact of the dry epidemic on migration flows in the region.
Fresh genetic analysis
It was previously thought that kuru led to a decrease or even complete cessation of marriages between the Fore and neighboring communities, as it attributed the disease to witchcraft.
The new genetic analysis found no evidence of a decline in overall migration to areas where the dryness was most severe, nor of a halt to the practice of patriarchy, in which a bride moves to live closer to her husband’s family.
“In contrast, we observed a significant bias against women among immigrants to areas with high rates of dry cases,” the authors wrote. The analysis showed that the proportion of women among migrants was 25% higher in dry areas with “high” cases than in “zero/low” dry cases.
“This probably reflects the continued practice of patriarchy [where a newlywed couple lives near the husband’s family] “despite the documented fears and pressures placed on communities as a result of the exchange rate,” the article concludes.
Field staff from affected and neighboring populations were recruited by the Papua New Guinea Institute of Medical Research (PNGIMR) to collect genetic samples through long-term community engagement, which were then analyzed by researchers in London and Copenhagen.
It’s really nice to find ways to look at human societies and human populations from more than one perspective.
Doctor Irene Gallago Romero
The researchers conducted a genetic analysis of the region based on genome-wide genotype data from 943 individuals from 68 villages and 21 language groups in the Eastern Highlands of Papua New Guinea; this includes 34 villages in the Southern Fore language group. dry.
Laboratory studies were approved by PNGIMR’s advisory committee and the research ethics committee of the UCL Institute of Neurology, with verbal consent from all participants before any samples were taken, and the involvement of relevant communities, village leaders, communities, families and individuals.
Previous genetic studies among the Fore people found that the surviving women carried genetic variants in the gene that codes for prion proteins, possibly making them resistant to kuru.
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Prof Simon Mead, consultant neuroscientist and clinical lead at the UK National Prion Clinic, said: “We found evidence that the fore population has evolved to protect itself against the kuru epidemic, but this region has been poorly studied in the past, so we sought to delve deeper into the genetics of the populations involved.” “We cannot make reliable inferences about evolution without knowledge.”
Dr. D., a researcher in human genomics and evolution at the St. Vincent Institute of Medical Research. Irene Gallago Romero said the question remains whether female migration is so severe that it changes the genetic makeup of traditionally insular communities.
Romero said the study found a “striking level of population structure,” or distinct genetic groups, in the region, but that a smaller level of population structure would have been observed if strict village boundaries had actually been broken down.
He said it was “striking” that the study showed how genetics could add another dimension to the history of a relatively unknown group of people.
“[Anthropology] and genetics tell mostly complementary stories, but there are parts that are inconsistent.
For example, the research found that some villages speaking different languages are genetically similar, while some communities speaking the same language are genetically different.
“So it’s really nice to find ways to look at human societies and human populations from more than one perspective.”
Another important finding was the existence of serious genetic differences between linguistic groups. The researchers found more differences between communities in Papua New Guinea than between Spain and Finland; however, some of these groups were only 45 km apart. Gallago Romero attributed this to the practice of marrying within a small community.
Colin Masters, an award-winning professor of neuropathology at the University of Melbourne, said the study showed how pandemics and epidemics, in which millions of people die, have the potential to alter a population’s genetic code.