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Why Are People Left- (or Right-) Handed?
Live Science ^ | November 10, 2019 | Megan Gannon

Posted on 11/22/2019 4:44:45 AM PST by SunkenCiv

While there's no righty or lefty gene, DNA does seem to play a role in handedness. In a recent study published in Brain: A Journal of Neurology, researchers at the University of Oxford looked at the DNA of about 400,000 people in the U.K. and found that four regions of the genome are generally associated with left-handedness. Three out of these four regions were involved in brain development and structure. Some researchers hope that studying the biological differences between lefties and righties could shed light on how the brain develops specializations in its right and left hemispheres...

Righties have dominated for as far back in the archaeological record as researchers can see, about 500,000 years, Uomini said. Neanderthals, our now-extinct human cousins, were also strongly right-handed.

That makes humans pretty strange among animals. Several nonhuman species, such as the other great apes, are individually handed, but the split between righties and lefties is typically closer to 50-50.

What caused our extreme bias toward right-handedness to evolve and persist? From an evolutionary perspective, if right-handedness evolved because it had some kind of advantage, then you might expect left-handers to disappear completely, Uomini told Live Science. She added that there are some disadvantages to being left-handed, such as higher frequencies of work accidents. Researchers also linked left-handedness to learning disabilities, in a study published in 2013 in Brain: A Journal of Neurology.

But there's a leading theory to explain why left-handers have maintained a constant minority: the fighting hypothesis.

"The idea is that in hand-to-hand combat, or in combat with weapons, there is an evolutionary advantage to being a minority left-hander," Uomini said. "If you're left-handed, you have a surprise advantage because most people are used to fighting against right-handers."

(Excerpt) Read more at livescience.com ...


TOPICS: History; Science; Travel
KEYWORDS: dna; godsgravesglyphs; helixmakemineadouble; lefthandedness; southpaws
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To: OrangeHoof

My youngest brother seemed to be leaning to be left-handed as an infant, then broke his left collar bone as a toddler (from a fall, I SWEAR). I think he had to wear a sling for a couple months, but truly don’t remember the details. He ended up being right-handed.


61 posted on 11/22/2019 6:23:33 AM PST by NEMDF
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To: abclily

Paul McCartney is a lefty. Made the Beatles look very symmetrical up there!


62 posted on 11/22/2019 6:24:25 AM PST by freepertoo
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To: Newbomb Turk

Definitely would make one very, very attentive.

Princess Bride — the swordfight
https://www.youtube.com/watch?v=WDlZ_SXx5gA


63 posted on 11/22/2019 6:25:10 AM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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To: gimme1ibertee
And I know that I am in the same sort of company as these ladies, lol (Martina McBride and Katie Pavlich).
64 posted on 11/22/2019 6:25:14 AM PST by OttawaFreeper ("The Gardens was founded by men-sportsmen-who fought for their country" Conn Smythe, 1966)
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To: SunkenCiv

I have mirror image identical twins. Even their teeth came in opposite. Still wonder how that happens.


65 posted on 11/22/2019 6:31:11 AM PST by luckystarmom
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To: SunkenCiv

I’m totally serious, it’s a real thing! Hopefully I am not the only one who has noticed this inconvenience? lol


66 posted on 11/22/2019 6:31:25 AM PST by Openurmind (The ultimate test of a moral society is the kind of world it leaves to its children. ~ D. Bonhoeffer)
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To: JPJones

Ferniehirst Castle, Clan Kerr.


67 posted on 11/22/2019 6:32:22 AM PST by Sparky1776
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To: luckystarmom

:^) Yeah, that’s pretty cool, pretty rare too.


68 posted on 11/22/2019 6:33:18 AM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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To: Tennessee Conservative
re. I don’t know if I qualify as ambidextrous since I can only do certain things with a certain hand.

Same with me - eat and write left, right for just about everything else except racket sports like tennis or squash, but am not ambidextrous. If someone asks me if I'm right- or left-handed, I just say "yes". ;-)

69 posted on 11/22/2019 6:35:24 AM PST by ken in texas
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To: Tennessee Conservative

Being ambidextrous amazes me. RH here and nearly helpless with left in anything that requires fine-tuning.


70 posted on 11/22/2019 6:39:50 AM PST by gloryblaze
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To: Newbomb Turk

Yet when you design tools to be ambidextrous — think about the Colt CAR-4 rifle — you see an unusually high number of left-handed shots among soldiers & Marines. Didn’t used to be the case in earlier wars when bolt action rifles prevailed. I notice this constantly in photographs from Desert Storm, Operation Iraqi Freedom & Afghanistan. So there is a training component to this?

If tools & training are flexible enough to allow an individual to try it either way, suddenly the percentage of lefties for that activity goes way up.

Look at all the left-handed shots in Ice Hockey.


71 posted on 11/22/2019 6:39:51 AM PST by Tallguy (Facts be d@mned! The narrative must be protected at all costs!)
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To: OttawaFreeper

Counsins in maternal side are left handed and one in paternal side. Both my husbands siblings are left handed. It’s a pain at the dinner table. At thanksgiving we have to find corners for them if the sit next to righted handed peiple.


72 posted on 11/22/2019 6:47:52 AM PST by gcparent (Justice Brett Kavanaugh)
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To: Openurmind

Y’know, now that I think about it, the last few loaves of bread I bought were left-handed...


73 posted on 11/22/2019 6:49:30 AM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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To: ken in texas

LOL, my husband said I should qualify as handicapped since I’m a left-handed, redheaded female. :-) Sometimes it truly is a handicap.


74 posted on 11/22/2019 7:03:31 AM PST by Tennessee Conservative
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To: gloryblaze

I have met people that were left handed or right handed and couldn’t use the off hand for much of anything. I think that would difficult. I’m glad I’m like I am but it does cause the occasional brain confusion.


75 posted on 11/22/2019 7:05:05 AM PST by Tennessee Conservative
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I’m a righty, but when I got my first computer in 1996, I purposefully trained myself to use my left hand on the mouse, which gave me easier access to the enter and arrow keys. Drives my kids crazy!


76 posted on 11/22/2019 7:08:59 AM PST by Concentrate (ex-texan was right and Always Right was wrong, which is why we lost the election.)
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To: Tennessee Conservative

I could have written your post (except I have no confusion when someone tells me to turn left or right) . I write, eat and shave left-handed. Most other things I do right-handed. I think they call people like us “multidextrous”.


77 posted on 11/22/2019 7:10:56 AM PST by Sans-Culotte (With every passing day, I am a little bit gladder that Romney lost in 2012.)
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To: gcparent

At our family dinners at the grandparents’ place back in the 1970s and ‘80s, me and my eldest cousin (she was the first born of our generation and I was the first male child of our generation) would be seated next to each other because of both being left handed.


78 posted on 11/22/2019 7:12:52 AM PST by OttawaFreeper ("The Gardens was founded by men-sportsmen-who fought for their country" Conn Smythe, 1966)
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To: Concentrate

But I also figured it would lessen the possibility of developing carpel tunnel syndrome.


79 posted on 11/22/2019 7:13:00 AM PST by Concentrate (ex-texan was right and Always Right was wrong, which is why we lost the election.)
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To: SunkenCiv
I am right handed because one summer (when I was about. kindergarten age) my mother read some article in one of those magazines that are by the check out counter at the grocery store. It detailed that ambidexterity was somehow tied to dyslexia

So my mother began making me spend time with my left arm tied in front of my stomach.

80 posted on 11/22/2019 7:17:04 AM PST by MrEdd (Caveat Emptors)
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