Are you a rightie or a leftie? No, we're not talking politics here, we're talking handedness. And unless you happen to have an abundance of left-handed friends, you might have noticed how rare they are. So why are just1 in 10 of us left-handed?
While no one's been able to definitively explain this, there are plenty of hypothesesthat have beenbuilding for more than a century, and the evidence points to some kind of genetic influence. Why? Because the percentage of lefties is roughly the same,anywhere you look on the globe.
For those of you who kick a ball on a regular basis, you'll be aware that there are natural asymmetries all over the body - you'll likely opt for one foot over the other when you go to kick.
These asymmetries can be found in everything from our feet to our ears, our eyes, and the layout of our brain, Hannah Fry explains over at BBC Future.
If you hold your thumb at arm's length, then look at it using one eye and then the other, the eye that appears to show the thumb closest to you is your strongest. Similarly, you probably tend to answer the phone or listen behind closed doors with one ear rather than the other - that's your strongest ear.
But why aren't left-handed and right-handed people born to a roughly 50:50 ratio?
Some experts suggest thatsocial cooperation, played out over thousands of years, has given righties dominant. In other words, when communities act together - in terms of sharing tools and living spaces - using the same hand as everyone else is beneficial.
Others suggestthatit's to do with the way the brain is arranged in two hemispheres, with the left half controlling the right side of the body, and the right half controlling the left side of the body.
If most people's brains use the left hemisphere to control intensive language and fine motor skills, the thinking goes, that bias results in the right hand being more dominant too.
In fact, one of the more unusual hypotheses to explain the rarity of left-handedness is that a genetic mutation in our distant past caused the language centres of the human brain to shift to the left hemisphere, effectively causing right-handedness to dominate, Alasdair Wilkins explains forio9back in 2011.
And while genetics likely play a large role in determining handedness, it's probably not the whole answer. Left-handed parents are more likely to have left-handed children than right-handed parents - a preference that can even be seen in the womb - but they still tend to have more right-handed children overall.
Researchers have struggled to identify exactly which genes are responsible for increasing the chances of being a leftie.
In 2019, an analysis of 400,000 individual records revealed the first genetic regions associated with handedness - four of them, to be exact.But otherresearchsuggests that there are probably dozens of genes that play a role in determining whether we end up writing with our left hand or our right.
On top of that, other studies have linked factors such asoestrogen levels and birth position to varying levels of left- and right-handedness.
In short, there seem to be a lot of considerations at play, and researchers are having a hard time tying them all together. That meanswe can't yet tell you exactly why you were born left or right-handed, but scientists clearly are working hard at finding an answer.
And when they do, they'll have to explain why some of us appear to be ambidextrous, too.
A version of this article was first published in October 2016.
- How to use precision medicine to personalize COVID-19 treatment according to the patients genes - TheStreet - September 2nd, 2020
- Meiotic chromosome synapsis depends on multivalent SYCE1-SIX6OS1 interactions that are disrupted in cases of human infertility - Science Advances - September 2nd, 2020
- Thought to Be Extinct, New Guinea's Singing Dogs Found Alive in the Wild - Smithsonian Magazine - September 2nd, 2020
- Humans have had mystery DNA for 300,000 yearsand now we might finally know what it is - SYFY WIRE - August 10th, 2020
- The Secret to a Long, Healthy Life Is in the Genes of the Oldest Humans Alive - Singularity Hub - August 10th, 2020
- LogicBio Therapeutics Reports Second Quarter 2020 Financial Results and Provides Business UpdatesFDA Clears IND Application for LB-001 for the... - August 10th, 2020
- Research on Tasmanian devil offers new insights into tackling human cancer - National Science Foundation - August 10th, 2020
- Human Genetics Market 2020 Size by Product Analysis, Application, End-Users, Regional Outlook, Competitive Strategies and Forecast to 2027 - Owned - August 10th, 2020
- University of Texas researchers find mutation that led to 2015-2016 Zika outbreak - Homeland Preparedness News - August 10th, 2020
- Blood lipid levels may be altered in some autistic people - Spectrum - August 10th, 2020
- NIH taps Dr. Lindsey Criswell as director of the National Institute of Arthritis and Musculoskeletal and Skin Diseases - National Institutes of Health - August 10th, 2020
- 'Hyper urban' coyote genomes are growing apart from their city and rural cousins - Massive Science - August 10th, 2020
- Why scientists are worried about a 'Warp Speed' COVID-19 vaccine - New Haven Register - August 10th, 2020
- Gyroscope Announces Appointment of Leaders in Retinal Disease, Gene Therapy and the Complement System to Its Clinical and Scientific Advisory Boards -... - August 10th, 2020
- Noel Rose, Who Demonstrated Autoimmunity Exists, Dies at 92 - The Scientist - August 10th, 2020
- Invasion of the Body Snatchers: Viruses Can Steal Our Genetic Code to Create New Human-Virus Genes - SciTechDaily - August 10th, 2020
- Holder pasteurization of donated human milk is effective in inactivating SARS-CoV-2 - CMAJ - August 10th, 2020
- Dinosaur diagnosed with bone cancer that afflicts humans today - CNN - August 10th, 2020
- LogicBio Therapeutics Reports Second Quarter 2020 Financial Results and Provides Business Updates - GlobeNewswire - August 10th, 2020
- The Secret to Healthy Longevity Is in the Genes of the Oldest Humans Alive - Singularity Hub - August 10th, 2020
- BU's COVID-19 Testing Passes Its First Test | BU Today - BU Today - August 10th, 2020
- COVID-19 in Africa: Dampening the storm? - Science - August 10th, 2020
- Pacific Biosciences and Asuragen Collaborate to Develop Assays for Carrier Screening and other Applications Based on SMRT Sequencing Technology and... - August 10th, 2020
- U of T researchers identify molecular switch allowing parasites to survive inside hosts without oxygen - News@UofT - August 9th, 2020
- LUMINEX : MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS (form 10-Q) - marketscreener.com - August 8th, 2020
- Gaucher Disease Treatment Market Size, Top Companies, Trends, Growth Factors Details by Regions, Types and Applications - Owned - August 8th, 2020
- How studying genetics and lifestyle can shape a healthier MENA region - The European Sting - August 8th, 2020
- Detection of H1 Swine Influenza A Virus Antibodies in Human Serum Samples by Age Group - CDC - August 7th, 2020
- UW researchers devise approach to treat rare, incurable form of blindness - University of Wisconsin-Madison - August 7th, 2020
- Prevail Therapeutics to Present at 2020 Wedbush PacGrow Healthcare Conference - Stockhouse - August 7th, 2020
- human genetics | Description, Chromosomes, & Inheritance ... - August 6th, 2020
- Human Genetics | Pitt Public Health | University of Pittsburgh - August 6th, 2020
- Triplet Therapeutics To Present at Upcoming Events - Business Wire - August 5th, 2020
- 'Hyper urban' coyote genomes are growing apart their from city and rural cousins - Massive Science - August 5th, 2020
- Baylor genomics teams partner to provide COVID-19 testing for Houston area - Baylor College of Medicine News - August 5th, 2020
- Gaucher Disease Treatment Market (Impact of COVID-19) Top Growing Companies: Acetelion Pharmaceutical (J&J Ltd.), Erad Therapeutic Inc., JCR... - August 5th, 2020
- High-fat Diet and Genetics Lead to Anxiety and Depression in Rats - Newswise - August 5th, 2020
- 'Mono' virus turns on cancer-related genes. Here's how. - Live Science - August 4th, 2020
- Human Challenge Trial Neither Essential Nor Ethically Justified at This Time, Says US Expert Anthony Fauci - Yahoo India News - August 4th, 2020
- ICMR to host global web conference on science, ethics of COVID-19 vaccine starting 4.30 pm today - Firstpost - August 4th, 2020
- Faculty/staff honors: Women in engineering network nod, winning magazine article on geologic hazards and refugees and two national genetics society... - July 31st, 2020
- ENCODE3: Interpreting the human and mouse genomes - Science Codex - July 31st, 2020
- Revealing the intrinsic functioning of human and mouse genomes - Tech Explorist - July 31st, 2020
- Maternal Immune Activation Causes Schizophrenia-like Behaviors in the Offspring through Activation of Immune-Inflammatory, Oxidative and Apoptotic... - July 31st, 2020
- Podcast: The ancient war between genes and disease - Genetic Literacy Project - July 31st, 2020
- Pitt's School of Public Health welcomes students with opera about obstetrician who championed hand-washing - TribLIVE - July 31st, 2020
- BNGO Stock Price: BioNano Genomics Inc. retreats, starts week in the red - FXStreet - July 31st, 2020
- A Genetic Mutation Reveals How the SARS-CoV-2 Virus Strikes - Technology Networks - July 31st, 2020
- 88-Year Old Daniel Smith, Son Of Slave, Tells His Story - Moguldom - July 31st, 2020
- 23andMe Releases Devastating Analysis of Trans-Atlantic Slave Trade - Futurism - July 31st, 2020
- MSU researcher earns grant to study effects of droughts - MSUToday - July 31st, 2020
- Massive Growth in Human Genetics Market Breaking new grounds and touch new level in Upcoming Year by QIAGEN, Agilent Technologies, Thermo Fisher... - July 30th, 2020
- CEO of genome analysis firm: We have the data to prove people will take care of themselves - University of Miami - July 30th, 2020
- Researchers from U of T, Harvard study collective human behaviour amid COVID-19 - News@UofT - July 30th, 2020
- Gene mutations discovered as a trigger for male infertility - BioNews - July 29th, 2020
- Cerevel Therapeutics and Cyclica Announce Research Collaboration to Use Artificial Intelligence to Accelerate Discovery of Novel Medicines in... - July 29th, 2020
- Relatives of coronavirus may have been in bats for decades - Opelika Auburn News - July 29th, 2020
- Link between platelets and Covid-19 virus? - The New Indian Express - July 29th, 2020
- Fortress Biotech Announces Publication of Study on Targeted Next Generation Sequencing for Newborn Screening of Menkes Disease in Molecular Genetics... - July 29th, 2020
- New 23andMe Study Reveals the Genetic Legacy of Slavery in the Americas - Gizmodo - July 29th, 2020
- The Groundbreaking Scientist Who Risked All in Pursuit of His Beliefs - The New York Times - July 29th, 2020
- 23andMe and GSK Head to Clinical Trials With Cancer Drug - MSN Money - July 29th, 2020
- Human Genetics - David Geffen School of Medicine at UCLA - July 29th, 2020
- Discovering how genetic 'dark matter' plays a role in mental illness is just the tip of the iceberg for human health - The Conversation UK - July 29th, 2020
- Prevail Therapeutics Granted Composition of Matter Patent for Experimental Gene Therapy Program PR006 - GlobeNewswire - July 29th, 2020
- The toll of shrinking jaws on human health | Stanford News - Stanford University News - July 28th, 2020
- Global Hereditary Genetic Testing Market (2020 to 2030) - Analysis and Forecast - GlobeNewswire - July 28th, 2020
- Triplet Therapeutics nabs Scholar Rock R&D exec as new CSO - FierceBiotech - July 27th, 2020
- Meet Dr Sarah Gilbert, one of the scientists leading the race to find a coronavirus vaccine - The Indian Express - July 27th, 2020
- Genetic basis of bats superpowers revealed - KLBK | KAMC | EverythingLubbock.com - July 27th, 2020
- Study of Gene's Hormone Effects Leads to Surprise Insight into Pituitary Tumors - University of Michigan Health System News - July 26th, 2020
- Dutch University hospital Radboudumc finds genetic mutation as a reason for lack of defense against corona - Innovation Origins - July 26th, 2020
- Tailoring Depression Treatment With Genetics - Technology Networks - July 26th, 2020
- Genetic puzzle: How mice can be modified to help in the race to develop coronavirus therapies - Genetic Literacy Project - July 26th, 2020
- The genetic basis of bats' superpowers revealed - Newswise - July 26th, 2020
- Inside the Global Quest to Trace the Origins of COVID-19and Predict Where It Will Go Next - TIME - July 26th, 2020
- Baylor Genetics and the City of Houston Form COVID-19 Testing Partnership - PRNewswire - July 25th, 2020
- Triplet Therapeutics Appoints Alan Buckler, Ph.D., as Chief Scientific Officer - Business Wire - July 25th, 2020
- The genetic basis of bats superpowers revealed - YubaNet - July 25th, 2020
- Fireflies help kindle new tests and treatments for COVID-19 - TMC News - Texas Medical Center News - July 25th, 2020