Latest news with #1000GenomesProject
Yahoo
2 days ago
- Health
- Yahoo
Race and genetics do not line up well, new study confirms
When you buy through links on our articles, Future and its syndication partners may earn a commission. The racial and ethnic groups people identify with may not accurately represent their genetic backgrounds or ancestries, a new study of people in the United States suggests. This discrepancy between people's self-reported identities and their genetics is important for scientists to acknowledge as they strive to develop medical treatments tailored to different patients, the researchers behind the study say. "This paper is very important because it clarifies at the highest resolution the relationship between genomic diversity and racial/ethnic categories in the US," said study co-author Eduardo Tarazona-Santos, a professor of human population genetics at the Federal University of Minas Gerais in Brazil. The findings are "critical to develop appropriate precision medicine solutions for all," he told Live Science in an email. Precision medicine tailors treatments to individual patients, taking their genes, environment and lifestyle factors into account. In their study, published Thursday (June 5) in The American Journal of Human Genetics, Tarazona-Santos and his colleagues analyzed the DNA of more than 230,000 people who contributed to the All of Us research database. This trove of data has been compiled through a National Institutes of Health program aimed at advancing precision medicine by recruiting people from diverse and underrepresented populations. Historically, many large-scale genetics studies have predominantly included people of European ancestry, making efforts like the All of Us project crucial for reducing medical inequity. However, the program has faced significant funding cuts in recent months, which has significantly slowed recruitment and progress. Related: What's the difference between race and ethnicity? Using a method called principal component analysis, the team identified genetic similarities and differences among the people included in the database. They also used genetic catalogs that contain DNA samples from all over the world, such as the 1000 Genomes Project, as a way to assess how people's genetic ancestry compared with the racial (white, Black or African American, Asian American) and ethnicity (Hispanic/Latino or not) categories used in the All of Us questionnaire. People who identified as being from the same racial and ethnic groups had a number of genetic differences, the team found. In fact, "most genetic variance is within race and ethnicity groups rather than between groups," the study authors wrote in the report. Rather than sorting people into "distinct clusters" divided by racial and ethnic lines, the analyses found that people within different races and ethnicities show "gradients" of genetic variation. "We found gradients of genetic variation that cut across those categories," the authors wrote. The new study's findings counter a controversial paper published in Nature in 2024 that had also analyzed genomic data provided by All of Us participants. At the time, the paper was criticized by some experts, who argued that the technique used to analyze the race and ethnicity data could be misconstrued to support the incorrect idea that humans can be neatly categorized into distinct races. The new study, which used a different data-crunching technique, found the opposite. The research also found that, even within the same ethnic and racial group, people show genetic variation across different U.S. states. This could reflect the "historical impacts of U.S. colonization, the transatlantic slave trade, and recent migrations," the authors wrote. A key example of this was seen in participants who identified as Hispanic or Latino and lived in states like California, Texas and Arizona, who were found to have a high proportion of Native American ancestry compared with Hispanic and Latino people in other parts of the U.S. This makes sense considering many of these states were historically part of Mexico, which has a large population of people with mixed Indigenous and European ancestries, the researchers argued. By contrast, of people who identified as Hispanic or Latino, those in New York were found to have the highest proportion of African ancestry, which is "consistent with recent migration from the Caribbean to New York." The authors said their findings show that the genetic backgrounds of people in the U.S. are highly complex and that "social constructs of race and ethnicity do not accurately reflect underlying genetic ancestry." In light of this, the researchers have said they "do not recommend using race and ethnicity as proxies for ancestry in genetic studies." RELATED STORIES —'Racism is a global public health crisis': Author Layal Liverpool says racist ideas still pervade medicine, and that hurts all of us —Scientific consensus shows race is a human invention, not biological reality —Racial bias is baked into algorithms doctors use to guide treatment Tesfaye Mersha, a professor of pediatrics and a human genetics researcher at Cincinnati Children's Hospital Medical Center and the University of Cincinnati, said that he agrees that these self-reported categories should not be used in genetic studies. Instead, the categories should be confined to social studies "where we know they will have a big impact," he told Live Science in an email. That said, Mersha also warned against overinterpreting the study's takeaways about regional and state-level genetic variation. "Some states had very low participant numbers, which may skew regional estimates and limit generalizability," he noted. "Moreover, high population mobility across states blurs geographic boundaries, especially in the absence of multigenerational ancestry data," he said. In short, because people move around a lot, it's difficult to draw conclusions without having a clear sense of how long their families have been based in a given state.
Yahoo
20-03-2025
- Science
- Yahoo
Our Genes Reveal Mysterious Split in Human Population 1.5 Million Years Ago
We've long assumed our species evolved from a tidy, single stream of ancestors. But life on Earth is never quite so straightforward, especially not when it comes to the most socially complex species we know: humans. University of Cambridge researchers have now uncovered an estrangement in our family tree, which began with a population separation 1.5 million years ago and a reconciliation just 300,000 years ago. What's more, according to their analysis of modern human DNA, one of these isolated populations left a stronger legacy in our genes than the other. "The question of where we come from is one that has fascinated humans for centuries," says geneticist Trevor Cousins, first author of the published study. In biology, we often describe genetics and evolution with the metaphor of a branching tree. Each species' lineage begins with a 'trunk' at the base that represents a common ancestor, shared by all species at the crown. As we trace the tree from base to tip, which represents evolutionary time, its trunk forks, again and again, each split representing an irreconcilable rift in populations that meant they could no longer breed with each other, and thus became separate species. What an evolutionary tree does not capture is the on-again/off-again nature of intra-species dynamics, the many near-misses where one breeding group diverges into two, and then blends again back to one. In some situations, this makes quite a mess of the neat and tidy tree diagram, and calls into question where the precise 'species' cutoff is. "Interbreeding and genetic exchange have likely played a major role in the emergence of new species repeatedly across the animal kingdom," Cousins says. Cousins and his co-authors, Cambridge geneticists Aylwyn Scally and Richard Durbin, had a hunch this kind of family drama would apply to our own species, Homo sapiens, which is technically more like a subspecies, except that there aren't any other groups left. Aside from humanity's general penchant for love and war, there's some proof we 'spliced branches' with the Denisovans, and with a fair bit of Neanderthal DNA in our gene pool to this day, we know species lines must have blurred there, too. The team used a statistical model based on the likelihood of certain genes originating in a common ancestor without selection events intruding. This was then applied to real human genetic data from the 1000 Genomes Project and the Human Genome Diversity Project. A deep-rooted population structure emerged, suggesting modern humans, Homo sapiens, are the result of a population that split in two about 1.5 million years ago, and then, only 300,000 years ago, merged back into one. And it explains the data better than unstructured models, the norm for these kinds of studies. "Immediately after the two ancestral populations split, we see a severe bottleneck in one of them – suggesting it shrank to a very small size before slowly growing over a period of one million years," says Scally. "This population would later contribute about 80 percent of the genetic material of modern humans, and also seems to have been the ancestral population from which Neanderthals and Denisovans diverged." It suggests the human lineage became irrevocably tangled much earlier than we thought. For instance, Neanderthal genes are only present in non-African modern human DNA, making up about 2 percent. The ancient mixing event 300,000 years ago resulted in only about 20 percent of modern human genes coming from the minority population. "However, some of the genes from the population which contributed a minority of our genetic material, particularly those related to brain function and neural processing, may have played a crucial role in human evolution," Cousins says. "What's becoming clear is that the idea of species evolving in clean, distinct lineages is too simplistic." The research was published in Nature Genetics. DNA From Beethoven's Hair Reveals Surprise Nearly 200 Years Later Crucial Feature of Human Language Emerged More Than 135,000 Years Ago Mysterious Twist Revealed in Saga of Human-Neanderthal Hybrid Child
