New Genetic Study Reveals Females Were Dominant During Human History
The human population has been divided into male and female throughout human history. Now, though, scientists have examined human genetics and have found that females have long dominated worldwide populations, revealing a bit more about our genetic past.
In order to find out a little bit more about our genetic history, the scientists used a new technique to obtain higher quality paternal genetic information in order to analyze the demographic history of males and females in worldwide populations. More specifically, the researchers compared the paternally-inherited Y chromosome (NRY) with maternally inherited mitochondrial DNA (mtDNA) of 623 males from 51 populations.
Previous studies actually used different techniques to analyze NRY and mtDNA, which led to bias in the results. Yet this latest study used a high-resolution Y chromosome sequencing assay that allowed the scientists to get paternal and maternal histories of similar quality and resolution, so that they could make a direct comparison.
In the end, the researchers found that there are greater genetic differences in paternal NRY than in mtDNA. Yet these differences aren't as large as previously thought. What was more surprising was the fact that there was substantial variation in the relative amounts of NRY vs. mtDNA differentiation at the regional level.
The findings reveal that in African populations, there was a lower paternal genetic diversity. This could a result of the Bantu expansion into eastern and southern Africa that began around 3,000 years ago. The scientists also found higher maternal genetic diversity from the Americas, hinting that there were fewer males than females among the original colonizers.
"Our new sequencing technique removes previous biases, giving us a richer source of information about our genetic history," said Mark Stoneking, one of the authors of the new paper, in a news release. "It allows us to take a closer look at the regional differences in populations, providing insights into the impact of sex-biased processes on human genetic variation."
The findings are published in the journal Investigative Genetics.