When we think of our ancestors, our minds tend to move on to geography. We introduce our promoters by noting that they were Norwegian, Brazilian, Indonesian or members of a Native American tribe. Personal genetic tests, such as those offered by Ancestry and 23andMe, offer customers a travel record of their lines ’global journeys. And some of our most obvious phenotypic symptoms, such as hair and skin color, developed in relation to the lands that our ancestors called home.
Lost within this locked focus is the fact that social and cultural traits – how our ancestors lived together and interacted with each other – also influence gene flow. In doing so, these factors shaped our evolution and genetic diversity. As a new study has found, for the people of the Indian sub-region, such social and cultural factors may be more important to their genetic diversity than the deserts, grasslands and forests. tropical in between.
A new kind of mother tongue
Map showing the location of 33 Indian populations along with plot graphs showing the relationship between sociolinguistic groups and genetic structures.
Credit: Molecular Biology and Evolution
The new study, published in Molecular Biology and Evolution, began when Aritra Bose, who earned her doctorate at Purdue in genetics and data science, examined the close links between genes and geography in Europe. Originally from Calcutta, India, Bose wondered if such a strong connection would be true of his home country. He teamed up with Peristera Paschou, a population geneticist and associate professor of biological sciences at Purdue University, and Petros Drineas, associate head of Purdue’s Department of Computer Science, to find out. “Our genome has the signature of our ancestors, and the genetics. Today’s numerical structure has been shaped by evolutionary forces. What we are looking for has led different groups of humans to come together and what sent them away, “Paschou, who led the investigation with Drineas, said in a press release. “To understand the genetics of human populations, we have created a model that allows us to consider together many different factors that may have shaped genetics. “The researchers developed a computer model called COGG (Correlation Optimization of Genetics and Geodemographics) to study the genetic substructure of a population. They then feed COGG a data set containing 981 individuals from 90 groups. Indian, later coming together with a data set of 1,323 people from 50 Eurasian populations.The model shook the numbers and found something amazing.The genotype and geography are usually strongly correlated looking at European figures As one National Geographic writer put it when discussing a study published in Nature: “The result was amazing – Europe ‘s genetic and geopolitical maps are going involved to an incredible extent. On the bilateral genetic map, you can see the Italian shoe and the Iberian Peninsula [sic] where Spain and Portugal sit. The Scandinavian countries appear in the correct order and in the southeast, Cyprus is particularly close to the ‘coast’ of Greece. “Such symmetry of the geo and genome was not found in the study of the -India; in fact, the analysis showed a weak correlation between genotype and geography.Instead, shared language was the main genetic link.The researchers found that people who speak the same language were many more likely to be closely related, regardless of where they lived in the subcontinent, for example, their analysis showed that Indo-European and Dravidian speakers shared a genetic shift with Europeans, while Tibeto-Burman speaking tribes shared with East Asians Social structure also showed a stronger correlation than geography in their analysis The researchers found that this correlation originated in the social strata which put the caste system of India a n involved rma (work) and dharma (duty). Marriage was strictly confined within a man’s caste, leading to a long history of endogamy. Although the caste system was effectively abolished in 1950 by the Indian government, that endogamy kept Indian society under control long enough to make a powerful impact on the country’s historical gene flow. “Our results clearly show that endogamy and language families are crucial in studying the genetic stratification of Indian numbers,” the researchers write in the study.
New dimensions for understanding ancestry
This is not to say that geography played no part in the ancestral gene flow of India, and that genotypes across Europe were not influenced by social and cultural factors. They certainly did. That nature study found, for example, language-based genetic collections in Switzerland. And perhaps Europe’s geographical spread has more to do with historical sociopolitical issues than environmental ones.
The point of both studies, however, is not to connect our genetic history to land or language, but to understand how genes flowed through historical associations.
“It sheds light on how genetics works in our society,” Bose said in the same news. “This is the first model that can take into account social, cultural, environmental and linguistic factors. which shapes the gene flow of numbers. It helps us to understand what factors contribute to the genetic puzzle that exists in India. It destroys the puzzle. “
With better knowledge of historical gene flow, scientists may be able to better research biomedical research to better detect rare genetic changes, assess individual risks for specific diseases, and predict what numbers that may be more susceptible to certain drugs. By opening up the pathways we use to understand our genetic history, we can hopefully advance that knowledge and understanding.