Polygamy's mark on the human genome

Polygamy left its mark on the human genome--comment at bottom [2 articles]

* 01:00 26 September 2008
* NewScientist.com news service
* Ewen Callaway

Throughout human history, relatively few men seem to have had a greater input into the gene pool than the rest, suggests a study of variations in DNA.

Tens of thousands of years of polygamy has left a mark on our genomes that is a signature that small numbers of males must have mated with lots of females.

Over time, such a pattern will spawn more genetic differences on the X chromosome than other chromosomes. This is because women have two copies of the X, while men only one. In other words, the diversity arises because some men don't get to pass on their genes, while most women do.

"Humans are considered to be mildly polygynous and we descend from primates that are polygynous," says Michael Hammer, a population geneticist at the University of Arizona in Tucson.

Polygyny refers to the practice of males mating with multiple females, and its most common form in humans is polygamy or multiple marriages.

To find our hidden genetic history, Hammer and his colleagues sequenced DNA from 90 people belonging to six groups: Melanesians, Basques, Han Chinese, as well as three African cultures: Mandenka, Biaka and San.
Long tradition

Hammer's team discovered more genetic differences in the X chromosome than would be expected if equal numbers of males and females tended to mate, over human history. The only explanation for this pattern is widespread, long-lasting polygyny, he says.

His team's analysis reflects all of human history, and modern monogamy has not even left a blip in our genomes. "I don't know how long monogamy has been with us," Hammer says. "It seems it hasn't been around long, evolutionarily."

Besides, "most societies practice some form of polygamy", he says. Even if most Western men don't take multiple wives, men tend to father children with more females than females do with males, a practice called "effective polygamy".

"It's not unexpected," says Dmitri Petrov, an evolutionary geneticist at Stanford University in California. "Polygany is something you would expect to find." Petrov and his colleagues uncovered the same genetic pattern in fruit flies.

Journal reference: PLoS Genetics (DOI: 10.1371/journal.pgen.100202)


On Dream Boys, Polygamy, May-December Affair Syndrome and Everything in Else in Between

September 28, 2008 in Essays and Opinion | Tags: miles domingo, relationships

I took up ecology last summer as one of my majors. I’ve always liked this branch of Biology because its applications only require the use of common sense, and much of the principles that it tackles are very much observed in the real world. If you’re looking for examples and applications for ecological principles, you need not look farther than your own backyard, so to speak. Ecology can actually explain the existence of certain human behaviors, customs and norms based on their biological significance. What’s more interesting is ecology can actually turn the tables around with regards to what we consider evil and immoral using our very nature as surviving species as explanation.

Take human relationships, for example.

The principles that govern our need for loving relationships outside of family are very complex. Today, we see bachelorettes constantly searching for Mr. Right. They even list many characteristics that they deem to be ‘perfect’, i.e. tall, dark and handsome. Except in communities that allow it, it’s against the law to have multiple wives. Churches and many a society encourage monogamy and condemn polygamy. Women, whose husbands are unfaithful—-men with affairs, or worse, another family— are considered the “victims”, for the blow of their spouse’s action land on them the hardest. Also, most adulterers are male, few are female. Moreover, it’s observed that the women who actually are the third wheels to these adulterous unions are younger than the original wife. But what’s actually surprising is that ecologically, all of these complexities have simple roots to the need to prove survival by reproduction. Another interesting thing to note with regards to polygamy and young girls going for older men is that no matter how feminist groups condemn and oppose them, we, the female species have actually condoned polygamy and the May-December affair syndrome because of the need to reproduce and propagate, the ultimate proof of species survivorship.

For humans, it’s not new to see single women attracted to men older than they are, or married men with 5 kids. This “wrong” desire for a family man actually is rooted to a genetic and consequently, an ecological cause. Survivorship, or the ability of an organism to withstand stresses in the environment is ultimately measured by the capability of the organism to reproduce despite all of these environmental pressures and constant fluctuation. A female has a limited reproductive potential (with regards to time) as compared to a male. A female releases an egg only once in a month, thus, it only has this one chance for it to bear offspring as compared to males who produce millions and millions of sperm everyday, which gives them virtually an unlimited reproductive potential. Furthermore, females undergo a menopausal stage, in which their limited “reservoir” of gametes are nearly used up. Only roughly half a thousand of eggs are to be released in her entire lifetime. Therefore, “A male that mates with a weak or otherwise unfit female loses only a small part of his reproductive potential; a female making a similar mistake may sacrifice all of hers.” (Lagunzad, 2008)

How does this relate to a bachelorette’s checklist, liking older men and polygamy, then? Utimately, these things and the choices that come with them roots from the genetic and ecological need of females to make a choice between making sure that this one chance of giving birth to offspring is a “sure fire shot” or a missed opportunity. “Perfection” and “dream guy” characteristics are most likely the characteristics that we see that would contribute to the likelihood that our children would have a strong genetic background, and so we want those characteristics to be mixed with, or more fittingly impregnated into our gene pool. Old age is often tagged with strength, maturity and potency because obviously, age allows for experience and it’s an evidence of your resistance to the destructive potentials of environmental fluctuation. More so if the male has offspring, because as said, reproductive capabilities are the ultimate proof of survivorship; having offspring ultimately makes a statement on your gene’s “incorruptibility” with regards to constant action of natural selection on the environment.

What about emotions? This explanation clearly takes the contribution of emotions and logic of choices that we make when it comes to walking down the aisle, marrying a DOM or having an underground affair with a married man. Research shows that bachelorette checklists do not get completely filled out with little checkmarks after all—most women marry men that miss out on the characteristics that they ascribed to their perfect mate. It’s a reality that women actually marry DOM’s or have affairs with married men because of pure logic and practicality—the money factor. While the genetic and ecological explanation is sound, we can’t simply reduce human complexity to the dictation of our genes. Our genes are not our guide dogs for the simple reason that we are not blind to need a guide dog at all.

While our genes do not ultimately determine the choices that we make, they clearly influence a large part of these cognitions, whether we are aware of them or not. The cognition that governs the fitness of the choices that we make with regards to the loving or romantic relationships we keep is another unexplored territory—another story to leave for the birds and the bees. . . .

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Comment [mine]
In anthropology, May-December marriages were called ''The European marriage pattern.'' I heard this from a UC Berkeley Graduate Student /House mate whose father had married a 26 year old after
his first wife died. He was eighty. My friend lived in a remote Swiss-German Canton. He fathered 10 children all tolled.

I said this was not uncommon in Utah, and mentioned a man I almost married at 20, he was man who was forty-three. I've regretted not doing it. [I'm 55.] We contemplated it from the time I was 19 until I was almost 24.

His father had 10 children total with the help of his much younger wife. Mormons emigrated to Utah, in the latter, generations of emigration, directly from Europe and had little positive contact with the outside. It has been linked to puritanical polygamy by the press and the situation with the removed children is surely tragic.

Long lived Georgians, who once were active as long as 160 years, and could remember their age only by reference to major events such as the CrimeanWar, practiced this marriage pattern predominantly.

There was a Soviet specialist, he went to high school in Russia because his father was in the Embassy, followed a friend who took her children to Moscow to attend an English Immersion Grade School while
she studied longevity in Soviet Georgia.

She found the May-December marriage pattern to be a key factor in longevity. Men could not marry until they were well established and they married women in their early to mid twenties.

All the shows would be at Pacifica Archives in Berkeley, CA. USA., associated with KPFA radio.

The Smith Act was in force from 1976-1996 or so. The last children
born when it was in force are 13 and fourteen now--this allowed
Polygamy and marriage soon after puberty to older men when this was
the traditional marital pattern of a religious group.

Forced arranged marriages were illegal wherever marital rape was illegal,
and, of course child sexual assault, ie. rape, is illegal anywhere in the US.

Anyway--Texas CPS timed their invasion for the year that the children
not covered by the Smith Act reached puberty.

Kathleen