Is an 'Evil' gene nonsense?
If lightning strikes a tornado...
I read that a Swedish scientist may have
discovered the 'Evil' gene that causes Man to kill, murder, start
wars etc. Is this 'discovery' another one of those theories classed
as nonsense? John, England
This is a Florida State mug shot of serial killer Ted Bundy, who
was tried and convicted of killing two women in Florida. Bundy
eventually confessed to killing 37 young women. "I'm the most
cold-blooded sonofabitch you'll ever meet. I just liked to kill, I
wanted to kill," said Bundy.
'Evil' is too complicated a concept for a scientific inquiry.
Let's limit the discussion to aggression or violence.
Perhaps you're referring to an article that appeared in New
Scientist about breeding fruit flies for aggression. Two
Greenspan, senior fellow, and
Herman Dierick, research fellow, of the Neurosciences Institute
in San Diego) managed, after 21 generations, to produce super
fighters that could outfight any fruit fly around. The super
'sluggers' started more fights, kept fighting longer and fought more
viciously than their sparring partners (the controls). They didn't
just chase and hit, but wrestled and flipped the other guys.
Greenspan and Dierick examined the flies' brains for possible
causes of the intense aggression. They found higher levels of an
enzyme (CYP6a20). Moreover, a single gene produces this enzyme.
They concluded a single gene caused the increased aggressive
Does that imply a similar, single gene in humans causes our
violence? Extremely unlikely.
"There is no single gene capable of producing criminal behavior
per se," writes
Raine (Richard Perry University Professor in the departments of
criminology, psychiatry, and psychology at the University of
Pennsylvania, who studies the criminal brain) in the
Psychopathology of Crime.
Could several genes act together, coupled with the 'right' sort
of an environment, drive some people to pathological violence?
Raine believes this to be the case — a genetic predisposition for
In fact, researchers studied a large number of males from birth
to adulthood, and found such a genetic predisposition, emails
Greenspan. A couple of studies showed a genetic variant in a
particular enzyme (monoamine oxidase-A aka MAOA) had a significant
impact on whether or not the man developed antisocial problems. A
male with low levels of the enzyme was more likely to veer toward
adult violence, if someone had severely abused him as a
child. High levels gave him protection against ending up in trouble
even if he had been mistreated earlier.
"A very interesting and emblematic example of the interactions
between genetics and environment," Greenspan says.
Single gene turns fruit flies into fighters, NewScientist.com,
Psychopathology Of Crime: CRIMINAL BEHAVIOR AS A CLINICAL DISORDER,
Academic Press, 1993
Scientists Discover a Genetic Basis (the absence of a single
gene) for Aggressive Behavior in Male Mice, John Hopkins
Caspi A, McClay J, Moffitt TE, Mill J, Martin J, Craig IW, Taylor
A, Poulton R.
Role of genotype in the cycle of violence in maltreated children.
Science. 2002 Aug 2;297(5582):851-4.
Kim-Cohen J, Caspi A, Taylor A, Williams B, Newcombe R, Craig IW,
MAOA, maltreatment, and gene-environment interaction predicting
children's mental health: new evidence and a meta-analysis.
Mol Psychiatry. 2006 Oct;11(10):903-13.
- A couple of years ago, researchers at Duke University (Terrie
Moffitt and Avshalom Caspi), did, indeed, discover a gene for
recidivist criminal behavior. I don't know if this is the same
finding the writer was referring to, but it certainly is
relevant. If I remember correctly, only men carry it (big
surprise!) - about 30% of them. It only seems to be activated if
it is coupled with a childhood of abuse (nature AND nurture both
Marlene Sanford, Greensboro, North
- [Marlene emailed neuroscientist Terrie
Moffitt, professor at Duke University, about the study. Moffitt
responds here. AH]. You are right that the gene, which is called
MAOA, was not connected with crime and violence unless the
individual had a history of maltreatment as a child. So, rather
than a gene for violence, instead this seemed to be a gene that
influenced how vulnerable or resilient children are to stress.
MAOA functions in the brain to mop up excess chemical messengers
between brain cells. Teams in seven countries have tested the
original 2003 finding by now, and overall it is still holding up.
It's small, but it seems to be there.
By the way, we tested this in boys only,
because MAOA is on the X chromosome. Boys only have 1 X, so it is
easy to test whether a boy has the vulnerable of resilient
genotype. Girls have 2 X's, so they are (wouldn't you know it)
more complicated. So far, it is not known how to tell which X in a
given girl is the active X, so we could not test if MAOA predicts
women's aggression among girls who have been abused as kids. It
might, but we cannot test for that.
Terrie Moffitt, Durham,
- To answer your "Evil Gene" question: No it isn't true, as
"evil" is not scientifically quantifiable, in particular, the
extremely complex behaviors given as examples, "murder", "start
war", cannot be defined scientifically. Justice systems, which
have a much lower standard of evidence, already have a difficult
time with such questions.
Vardi Ilan, Montreal, Canada
- It is remarkable how genes are credited with giving specific
capabilities and effects on an organism, without really asking
"why might it do that?"
A researcher, who was trying to develop a salmon suitable for
farming in waters that may periodically freeze, located the
"antifreeze" gene in flounder and spliced it into salmon.
Reportedly the antifreeze part did not work, but the resulting
fish grew much faster than the normal salmon. Gene isolation is
not as easy as it has been described in reports, because genes
create proteins, not individual features. Isolating a disease to a
gene is more direct, since the protein the gene creates might
represent a symptom.
A lot of the task of determining which of the billions of genes
has what effect is achieved mathematically: from sample
populations, try to correlate the presence of a characteristic
with the presence of a particular gene sequence in the genome. The
bigger the population sample and the more precisely defined the
characteristic, the better your chance of isolating something –
but not necessarily everything.
Nowhere in the above is there an attempt to define what purpose
the gene might be serving in the organism, so the characteristic
isolated may only be a byproduct of a much more wide-ranging set
of effects. Furthermore, it may only work in conjunction with
other genes, or there may need to be an environmental trigger that
actuates the gene’s response.
So somebody claims to have isolated an "Evil" gene, right? Are
we to believe that all "antisocial" activity (if you can define
that suitably clearly) is strictly the effect created by one (or
more) genes? Oddly enough, a lot of triggers for murders, wars and
other evils have been traced in people’s histories to have
environmental triggers. We also know that certain situations (like
a mob scene) can have a person perpetrate an act that they would
never have considered normally.
Chances are the personality traits associated with the "evil"
being sought are aggressiveness and lack of empathy. They’re also
associated with the entrepreneurial spirit and the risk-taker –
when we consider the positive side of the characteristics. In
short, even if there is a gene associated with "Evil" it is not
going to be working alone. The values induced by upbringing and
social position are going to influence how the behavior is
If individuals partake in "Evil" with no particular gain or
benefit expected, we consider them mentally ill. To date, there is
limited evidence that there is a major component of this being
passed from one generation to the next in families of "Evil"
people, which would happen with a gene. Therefore, it’s really
more likely that the gene being discussed is, at best, one of a
whole orchestra of potential sources of evil, and it’s when
multiple instruments all strike the right "chord" that a notably
Evil note sounds.
Bob Maxwell, Alton, Ontario , Canada
If lightning strikes a tornado...
What would happen if a lightning bolt hits a
tornado? Nick, Lewisville, USA
A tornado touching down on May 3, 1999 in
central Oklahoma. Photo courtesy of NOAA.
A tornado would scarcely notice lightning
discharging through it.
"The power surge is neither strong enough nor
long enough to disrupt the tornado vortex," emails lead forecaster
Edwards of NOAA's Storm Prediction Center.
The odds of a lightning bolt hitting a tornado
are extremely small. "I have watched a hundred tornadoes in person
and videos of hundreds more; I haven't seen any examples yet."
Lightning does strike sometimes in front of or behind the tornado,
which gives the illusion of actually hitting it.
Tornado winds, however, can change where
lightning might strike, says Edwards. As a negative electric charge
builds in the cloud and a positive charge builds in the ground, an
invisible charge channel "wiggles" down from the cloud, following
the path of least resistance to ground. But intense buffeting winds
can deform the zigzagging channel, and cause other branches to be
better paths. Then the electrical charges choose the better path to
neutralize the charge differential.
Thus, a tornado's winds can affect lightning,
but lightning can't disrupt a tornado's vortex.
online tornado FAQ, by Roger Edwards, NOAA
A SEVERE WEATHER PRIMER: Questions and Answers about TORNADOES,
National Severe Storms Laboratory
Langmuir Lab Researchers' Volcanic Lightning Study In Science,
New Mexico Institute of Mining and Technology
What causes lightning? WonderQuest
(Answered April 14, 2008)
Adding salt helps to melt road ice and freeze
ice cream — why the different effect?
Eye-color genetics, Unhappy scorpions, Eye-color evolution,
Twins heredity, Sundog name
your roads or sidewalks are frozen, you pour salt on them to
make the ice melt. But you also put salt in an ice cream
freezer to make the ice cream freeze. Why does the salt that
you put in the ice cream freezer have a different effect than
when you pour it on the frozen roads?
Catherine, Dubach, Louisiana
Strawberry ice cream. Photo courtesy of Lotus Head and
Actually, the effect is the same in those
two situations, but we look at different aspects. We put salt on
icy roads, because we know salty water freezes at a lower
temperature than water, so the brine will melt. And that's what
we want — to get rid of the ice on the road. We don't notice
that, in the process of melting the road ice, we have made the
road colder, because it takes energy to melt the brine. That
heat energy comes from the road.
But that's exactly what we want for the
ice cream. As the brine in the ice-cream freezer melts, it takes
heat from the custard, makes the custard colder and, eventually,
freezes the custard into ice cream. We definitely notice the
custard getting colder, whereas we didn't the road. Moreover,
the ice cream will continue to get colder until the temperature
drops to the freezing point of brine — about -6 degrees
Fahrenheit (-21 C).
"The nature of water is remarkable,"
Rod Nave, professor at Georgia State University. Consider a
kilogram (about a quart) of water. It takes only 1 food calorie
to raise that water 1 degree Celsius (1.8 F). But, at 0 C (32
F), we must extract 80 food calories to freeze the water,
and add 80 food calories to melt that kilogram of ice.
The calorific energy is huge: 80 food calories is almost
enough energy to fuel a person running a mile. "This remarkably
large energy associated with the freezing/melting transition of
water leads to some extraordinary scenarios like the one you
have described — if you force water to
melt by lowering the freezing temperature, it's going to grab a
lot of energy from somewhere!" emails Nave.
Homemade ice cream maker (and heat thermodynamics),
What color eyes should two blue-eyed
people make? Chastity, Somewhere, World
Many colors are possible for the offspring
of blue-eyed parents, including a child with brown eyes. Blue
eyes are most likely.
Eye color mocks easy rules. Mom has green eyes, Dad blue. How
did I get brown? WonderQuest
What do scorpions do when it rains?
Cly, Bristol, New Hampshire
Scorpions are most prolific and diverse in warm, dry lands,
although they exist almost anywhere on the globe.
So, when spring and summer rains fall on
dry-land species, these scorpions seek drier places — perhaps up
a slope. Houses and buildings near arroyos and river beds that
are normally dry, are also possible targets.
Scorpions, by Russell Wright, Oklahoma
(Answered April 21, 2008)
Why so many eye colors?
What caused the natural selection for eye color?
Sara, Lafayette, Indiana
"This is a very puzzling question at the moment — one that may take some
time to work out," emails
Richard A. Sturm,
Principal Research Fellow at the Institute for Molecular Bioscience at the
University of Queensland in Brisbane, Australia. Sturm is one of the
leading researchers of the world who delves into eye-color genetics.
A small selection of eye colors. Photo courtesy of Richard A. Sturm and the
Institute for Molecular Bioscience at the University of Queensland.
The general consensus among evolutionists is that eye-color variation came about as a side
product of skin-color selection. Humans most likely evolved in Africa.
The direct sunlight shining on the equatorial regions of Africa favored humans
with dark skin that gave protection against the sun's harmful radiation.
When Homo sapiens, however, moved out of Africa into northern regions,
darker-skin protection was no longer needed, and natural selection for dark skin relaxed.
Genes controlling eye and hair color may be
closely linked to those controlling skin color. So, when skin-color
selection relaxed, eye and hair color also also were free to change. Genetic freedom to mutate gave
rise to the many eye colors now found
among European-descent peoples.
There is no doubt, Sturm says, that
the genes controlling eye color also influence skin color, and contribute to the
lightning of skin in European peoples. But his personal viewpoint is that
the eye-color genes responsible for switching on blue or brown eye color have a
much greater impact on the color of a person's eyes than on the color of the
skin. Sturm has absolutely no evidence supporting his view yet, but he's
working on it.
"We need a more mechanistic understanding of OCA2 (eye-color) gene regulation
before we can go much further on what may have been the selection pressure."
So, to answer your question: we don't know yet what caused eye-color
selection. But we continue to speculate. Sturm discussed the issue
with his colleagues; some thought people with blue eyes "may have been able to
better stand the dark, depressing days of Northern European ice-age winters than
those with brown eye colour."
Indeed, recent Seasonal Affective Disorder (SAD) studies support this idea.
Goel et al found that among 165 depressed (bi polar disorder or major depressive
disorder) people that "darker-eyed patients were significantly more depressed
and fatigued [in the winter] than blue-eyed patients." He and his team
concluded that lightly pigmented eyes increase the amount of light the eyes
receive during the winter, which relieves depressive symptoms in vulnerable
populations. Terman et al found similar results.
Eye colour: portals into pigmentation genes and ancestry by Richard A. Sturm
and Tony N. Frudakis, TRENDS in Genetics Vol.20 No.8 August 2004.
symptomatology differentiates subgroups of patients with seasonal affective
disorder, by N. Goel, M. Terman and JS Terman, Depress Anxiety,
and scotopic light detection in patients with seasonal affective disorder and
control subjects by JS Terman and M Terman, Biol Psychiatry. 1999 Dec
(Answered May 5, 2008)
Mother's (not father's) genes can cause fraternal twinning
If a man has twins
running in his family, can he in any way cause his sex partner to become
pregnant with twins? I say 'no' because twins happen
either because two
eggs are available to be fertilized (fraternal twins), OR one egg splits
(identical twins). He can't influence either event. Julie, Nassau, Bahamas
Twin sisters. Photo courtesy of Dustin M. Ramsey and Wikipedia.
Genetics is complicated. You are mostly right, probably. Until
1977, the general consensus was: identical twins do not
run in families and, therefore, are not caused by either parent's genes. But
Harvey et al challenged this viewpoint in 1977. He reported 10 families
who had multiple pairs of identical twins, and suggested we reexamine the
question. Both mothers and fathers were represented in the identical-twin
parents of identical twins.
In 2004, Hamamy et al reported following one extended
multi-generational family and its thirteen sets of identical twins. Hamamy
hypothesized a gene accounting for the twins and traced it back five generations
to a common grandfather. If this theory proves correct, identical twins
may, indeed, be attributable to a father's genes.
On the other hand, there is no question but heredity can influence the probability
of fraternal twins, and due to the mother's genes.
"The probability of a subsequent twin pregnancy is increased 4-fold in
mothers of twins, and the risk of having dizygotic [fraternal] twins is roughly
doubled for women whose mother or sister has dizygotic twins," writes
Victor A. McKusick, professor at John Hopkins University.
How is the trait for fraternal twinning passed along through a family?
"Most experts on the subject believe fraternal twinning is transmitted only
through the female line either as a recessive trait or as a dominant
female-specific trait," emails
Mark Curran of
the San Gabriel Valley Perinatal Medical Group.
By the way, about twelve in every 1000 deliveries results in fraternal twins, but this
probability varies with ethnic group and geographic area, writes Curran. In Nigeria
fraternal twinning occurs at a rate of 49 twins per 1000 births. In Japan
the rate of fraternal twinning is 1.3 per 1000 births. Furthermore,
a comparison of twinning rates of 14 ethnic groups in California found twinning
rates per 1000 maternities of 13.20 for blacks, 10.05 for whites, and 7.18 for
Approximately three in every 1000 deliveries are identical twins. This
average seems to be the same worldwide and the reasons are uncertain.
causes identical twins?, WonderQuest
Twinning by Mark Curran, M.D., OB Focus
Twinning, monozygotic by
Harvey, M. A. S.; Huntley, R. M. C.; Smith, D. W, Journal of Pediatrics, 1977.
Familial monozygotic twinning: a report of an extended multi-generational
family by HA Hamamy, HK Ajlouni, KM Ajlouni, Australian Academic Press, 2004
Why are Sundogs called sundogs?
Lucy, Asheville, North Carolina
Photo courtesy of M. Metz and Wikipedia.
I was playing tennis on a cold winter's day when I saw my first sundog.
"Look!" I said to my partner, "There's a rainbow in that cloud!" "A
sundog," she replied. What a strange name, I mused.
Maybe the ancient Norse first started calling sundogs 'sundogs.' Norse
epic poems (the Eddas and the Edda, which dates from before 1000 AD) spoke of
two wolves hunting the Sun and the Moon. Perhaps the Norse poems pictured
one 'dog' running in front of the Sun and one after — as sundogs.
Jonas Persson of the University of Agder in Norway offers this interpretation in his essay, "Norse
In fact, the present Danish name for sundog is 'solhunde' (sol = sun, hunde
= hound, wolf or dog), emails Persson. The old Norwegian and Swedish names
are lost. 'Sundog' (meaning a small halo or rainbow near the sun) first
occurred in English literature in about the 1580's.
a sundog, and what causes it? WeatherQuesting
Norse constellations by Jonas Persson, Digitalis
(Answered April 7, 2008)