Montclair High School
Class Of 1960
Gene Mazzola's research paper
Are you tired of thinking about raging political issues? Here are some more neutral questions to ponder – thanks to Gene Mazzola. Gene is a chemist associated with the University of Maryland. You can contact him at emazzola@umd.edu
- What might cause double vision? After developing double vision, Gene noticed that the effect was especially “spectacular” when he flew over the Grand Canyon and saw all its rocky features doubled and far separated. What was the cause? At first, Gene thought the double vision was related to cataracts but an ophthalmologist told him that double vision is common in seniors, like us, where the eyes can no longer completely rotate outward to see far-away objects. Fortunately, this inability to focus was corrected easily with an eyeglass prescription that completely eliminated the double vision.
- Are you right-handed or left-handed? Does your hair swirl clockwise or counter-clockwise? Gene explains that a little-known relationship exists between a person’s “handedness” (left-handed or right-handed) and whether that person’s hair whorl swirls in a clockwise or counter-clockwise direction. (A “hair whorl” is a patch of hair growing in a circular direction around a center point, as on the top of the head.) Gene says, “I've been reading about this for over a decade, although very little material exists. I have spoken to most of my colleagues at both the University of Maryland and in the NMR (Nuclear Magnetic Resonance) community, and have only encountered 2 other people who knew about this phenomenon… . I continue to be amazed that virtually no one knows anything about this relationship.”
To read more about “Handedness and Hair Whorls” click on “Gene Mazzola papers” in the blue sidebar on the left side of the home page. It is the 12th item from the top.
- How do you cross your arms over your chest? How do you cross your legs? Gene writes, “I have also been thinking about common actions that may be influenced by whether we are right- or left-handed.Specifically, how do people fold their arms when they cross them across their chests? I've noticed that when I do this, the fingers of my right hand are visible while those of my left are tucked under my right arm. Obviously, the trick is to fold one's arms quickly and not think about it. I've also folded them in the opposite way, and I have to work at it, and it feels odd. Crossing one's legs when sitting could be another action that is influenced by handedness.
What do you think? You can contact Gene at emazzola@umd.edu
Handedness and Hair Whorls
by Gene Mazzola
Statistically, ca. 92% of humans are right-handed and ca. 8% non-right-handed or ambidextrous to various degrees. A little-known relationship exists between right/left-handedness and the direction of rotation of a person’s hair whorl. The author’s interest in this topic developed from an interest in stereochemistry and the “handedness” of many molecules.
When a relationship between handedness and hair-whorl direction was initially proposed, it was suggested that a direct correlation existed between the two phenomena, viz.: the hair whorls of right-handed people swirled in a clockwise direction while those of left-handed persons went in a counterclockwise direction.1 However, this appeared to be a possible oversimplification because hair whorls must necessarily rotate in one direction or another while handedness is more of a gradation from completely right-handed, to predominantly right-handed, to ambidextrous, to predominantly left-handed, and to completely left-handed.
The correlation between handedness and hair whorl direction has been studied to some degree.2-5 It should be noted that the following explanation is still a simplification in that more complex genetic anomalies, such as internal organs appearing on the opposite side of human bodies compared to where they are usually located, e.g. hearts on the right side, have not been considered in the following discussion. Additionally, partially and fully ambidextrous individuals have been included with left-handed people in the “non-right-handed group (NRH)” in an explanation of this phenomenon:
(1.) The biological factors that govern handedness also affect hair-whorl direction. Alleles are pairs, or series, of genes that can be dominant, or recessive, in determining hereditary characteristics. Organisms typically have two alleles for a specific trait, one being inherited from each parent.
(2.) Dominant alleles dictate both right-handedness (RH) and a clockwise (CW) hair spiral. Having even a single copy of a dominant allele yields a right-handed person, with a clockwise hair whorl, as is the case for most people.
(3.) Recessive alleles individually dictate clockwise or counterclockwise hair-whorl direction and also handedness preference. When both copies of the allele are recessive, there is a 50:50 chance of a person (i) being either right- or non-right-handed and (ii) having a clockwise or counterclockwise hair whorl.
Thus, if a person has a counterclockwise-rotating hair whorl, that individual must have two copies of the recessive allele but has only a 50% chance of being non-right-handed. Similarly, only half of the non-right-handed people, who again carry two recessive alleles, will have counterclockwise hair whorls. Looking at the population as a whole, the following patterns emerge:
(1.) People who have a dominant hair whorl-handedness allele are right-handed (RH), have clockwise-rotating (CW) hair whorls, and comprise ca. 84% of the population.
(2.) People who have two recessive alleles (and thus no dominant allele that would produce Case #1 above) exhibit the following characteristics and comprise ca. 16% of the population:
(A.) Half of those will be right-handed (RH, 8%)
(1) Half will have clockwise-rotating hair whorls (RH/CW: 4%)
(2) Half will have counterclockwise-rotating whorls (RH/CCW: 4%)
(B.) The other half will be non-right-handed (NRH, 8%)
(1) Half will have clockwise-rotating hair whorls (NRH/CW: 4%)
(2) Half will have counterclockwise-rotating whorls (NRH/CCW: 4%)
Thus, the hair whorls of ca. 92% of the population rotate in a clockwise direction: (i) all of the dominant-allele, right-handed people (#1, ~84%), (ii) half of the recessive right-handed people (2.A.1, 4%), and (iii) half of the non-right-handed people (2.B.1, 4%). The hair whorls of only ca. 8% of the population rotate in a counterclockwise direction: (i) the other half of the non-right-handed people (2.B.2, 4%), and (ii) half of the recessive right-handed people (2.A.2, 4%).
Right-handed persons thus comprise 92% of the population (Groups 1-23 below). Persons with a clockwise-rotating hair whorl have an 88% chance of being right-handed [84% (#1 above) + 4% (2.A.1)]. However, individuals whose hair whorls rotate in a counterclockwise direction have a 50% chance of being non-right-handed [#2.B.2].
References:
(1.) H. Brunner, Right or Left in Nature and Elsewhere, Wiley-VCH (1999).
(2.) A. J. S. Klar, Genetics, 165, 269-276 (2003).
(3.) A. J. S. Klar, Genetics, 170, 2027-2030 (2005).
(4.) C. Brodie, American Scientist, 92, 27-28 (2003).
(5.) A. A. Beaton and G. Mellor, Laterality, 12, 295-301 (2007).
The table below summarizes the above information for 25 groups of people (in increments of 4 percent with 4 persons in each group) regarding the occurrences of handedness and hair-whorl direction in a random collection of 100 people.
Handedness-Hair Whorl Correlation Percentages |
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RH CW Group 1 (4%) |
RH CW Group 2 (8% total) |
RH CW Group 3 (12% total) |
RH CW Group 4 (16% total) |
RH CW Group 5 (20% total) |
RH CW 6 Group (24% total) |
RH CW Group 7 (28% total) |
RH CW Group 8 (32% total) |
RH CW Group 9 (36% total) |
RH CW Group 10 (40% total) |
RH CW Group 11 (44% total) |
RH CW Group 12 (48% total) |
RH CW Group 13 (52% total) |
RH CW Group 14 (56% total) |
RH CW Group 15 (60% total) |
RH CW Group 16 (64% total) |
RH CW Group 17 (68% total) |
RH CW Group 18 (72% total) |
RH CW Group 19 (76% total) |
RH CW Group 20 (80% total) |
RH CW Group 21 (84% total) |
RH CW Group 22 (4%) |
RH CCW Group 23 (4%) |
NRH CW Group 24 (4%) |
NRH CCW Group 25 (4%) |
RH=right-handed, NRH=non-right-handed; CW=clockwise hair-whorl rotation, CCW=counterclockwise hair-whorl rotation; BOLD = dominant allele groups 1-21 (84% total), Bold Italics = recessive allele groups 22-25 (4% each). |