According to the largest research on left-handers, left-handers may not be as rare as you think. Scientists found that about one-fifth (18.1%) of people may be left-handed, but it may be 9.34%. Why left-handers have been an unsolved mystery of human evolution and human genetic research.
Researchers from the University of Athens and the University of St. Andrew compiled data from 2 million people in five different studies for analysis. Because the researchers defined different standards for left-handers, they obtained two different estimates. For example, the 9.34% of left-handers are actually left-handed people who are limited to manual work, but according to the loosest standards, 18.1% are left-handed.
The research can help scientists better understand how physical and psychological factors promote the formation of left-handers. The researchers say the study can provide a useful reference for different aspects of left-handed research. In addition to providing reliable data, the studies on which we collected data all have different standards for measuring left-handers. This study highlights the variability of these studies.
Understanding left-handedness helps us understand human evolution, and studies have shown that right-handedness is one of the hallmarks of humans and great apes. Although we intuitively classify left-handed and right-handed, the data from this study shows that the proportion of people who use different hands for different operations is almost the same as that of left-handed.
A study last year found four gene regions that may cause left-handers. The reason why left-handers have superior language skills may also be related to these gene regions. Although research has not been able to identify specific left-handed genes, it has been able to narrow the scope to certain regions of the genome. The researchers also found that left-handedness may be a byproduct of the development of the fetal brain in the uterus and human microtubules. Human microtubules form the skeleton of cells, and most of the supporting functions in human cells are performed by these internal scaffolds. The researcher of the study said at the time: “Many animals exhibit left-right asymmetry during development, for example: the snail shell is bent to the left or right, which is driven by the gene of the cell scaffold, we call it the ‘cytoskeleton’ . For the first time in the human body, we found that these left-handed cytoskeletons have different characteristics. “