A new genome-wide association study of over 1.7 million people may not give us all the answers, but it is bringing us closer to understanding the combination of factors that help produce our preference for a dominant hand .
“While some people have a lasting fascination with either the left or right hand or both, understanding why some people are left-handed and others’ right-handed is also an important research question, as austerity can affect brain structure and The way the functions differ is located within the brain, ”says geneticist Sarah Medlan from the QIMR Burgoffer Medical Research Institute in Australia.
Researchers have claimed that this is the largest study of its kind ever, the team found a change in 41 single DNA base pairings associated with the possibility of one person being left-handed, while seven others being obscured were added.
Unfortunately, however, this is certainly not the whole story. The team found that these base pairs only awarded about 12 percent of the variance in ‘sedness’, meaning that there are some more (or many things) that are making up our left or right-handed preferences.
One of the researchers at the University of Queensland’s geneticist David Evans explains, “The results of our analysis suggest that genetic factors may account for only a very small amount of variation, while environmental factors may play a much more important role. . ”
“This percentage was similar for ambiguity, meaning that playing a game or musical instrument with a hand or injury is likely to have a stronger role in a person’s ability to use both hands equally.”
In a genome-wide association study, researchers examine a large number of genomes, analyzing which small DNA changes are associated with a particular trait – such as heart disease, or, in this case, left-handedness.
In this study, researchers took data from the UK Biobank, 23andMe, and the International Handedness Consortium to create a mega database of genome variants – data from 1,766,671 individuals to be precise.
“A large number of participants are provided with the statistical power to detect the effect of a gene with little impact on the arm,” says 23andMe statistical geneticist Gabriel Cuellar-Partida.
“It also highlights why larger studies are needed to understand the genetic factors affecting other neurological symptoms and conditions and why participation in research studies is so important.”
People who are left-handed do not always have an easy time. Until relatively recently, many left-handed people were punished in favor of their left-handers, and even today, left-handed people live in a world largely designed for right-handed people is. As we all have a hand preference on it is a question that has stopped biologists for decades.
About 10 percent of the US, UK and Australia populations are left-handed, but the exact figure varies from country to country. We know that this preference begins to show, with more small movements in one hand before birth.
Other theories have suggested differences in our brain hemispheres, epigenetic factors, and may contribute to exposure to prenatal hormones.
This new study found that some genetic differences were in microtubule genes and brain morphology – meaning that early developmental research may be for some.
The researchers wrote in their paper, “In relation to mildness, microtubule proteins play a critical role during the development and migration of neurons, plasticity, and neurodegenerative processes.”
“The association between mildness and variation in microtubule genes also provides differences in left-hand prevalence left in various epidemiological disorders and some epidemiological studies.”
Therefore, although this new research is not final about why people are left-handed, right-handed, or bisexual, it is an exciting story.
The research has been published in Nature human behavior.