Parthenogensis

Concerning Straight Dope article:

New Scientist recently had an interesting article on the difficulties with parthenogenic birth, which bears some relation to the question posted by the reader.
Article here:
http://www.newscientist.com/nsplus/insight/clone/virgin.html

One interesting bit was the concept of a biological arms race between the sexes, with certain genes being activated by sperm, and counteracted by the egg.

This seems to be due to a difference in goals between the woman and the man.

The sperm selects for a maximum use of the woman’s resources, the egg tries to keep that in check.

Without the balance provided by the sperm’s side of the DNA, the resulting girl (if this technique were ever to produce successful results) would probably not survive.

Of course, if this whole battle between the sexes hadn’t ever started, this problem with overcompensating wouldn’t exist.

Kyber, thanks for the New Scientist URL. I had, as one of those “facts I once read but can’t remember where,” the fact that on the close order of one birth in a million (girls) was parthenogenetic, a natural clone of the mother. That would mean that, with world population having just passed 6,000,000,000, there are just about 3,000 girls and women alive today who literally had no father. Obviously, to post that with absolutely no backup is to expect vituperation from the “I want evidence” crew.

This reminds me of an old biology joke:

Q: What does the “H” in Jesus H. Christ stand for?

A: Haploid

Interesting that you bring this up now. Cecil has a column on parthenogenesis coming out in a couple of weeks.

Dave, that’s a weak variation of the original punchline: Hallmark:Because He cared enough to send the very best. :slight_smile:

Hallmark: That’s of what the Pentagon originally wanted to call the MX instead of Peacekeeper.

A brilliant way of putting it! It’s rare to find a phrase that suddenly snaps a whole subject into clarity. amd it always feels so nice when this happens.

I wonder whether any of the mothers or daughters are aware of the unusual nature of the conception? Would there be any way of telling whether a girl was born parthenogenetically? Could it happen even if the mother had a normal heterosexual sex life?

And has a natural-clone birth ever been cited as an example of divine intervention more recently than the well-known incident in the Middle East around 2000 years ago? :slight_smile:

can’t be that - parthenogenetic clone always has to be female - see Cecil’s column

JTI, almost on target. Consider the following:

Woman has XXY chromosomal makeup. Makes her fully female, but with some slight masculine characteristics (e.g., slimmer-than-normal hips, small bosom, slight tendency to facial hair). She has a parthenogenetic birth. One possible result is an XY offspring, i.e., a son. Alternate supposition: normal XX-composition woman has parthenogenetic offspring, but X chromosome fails to undergo mitosis. Result: single-X offspring. Now, IIRC, the Y chromosome carries few if any male-selection genes. The somatic chromosomes are what selects for maleness, unless overridden by the XX selecting for femaleness. So our single-X offspring is biologically male.

Highly improbable. But it might happen once in ten billion times or so.

Sounds impressive, but a single-X individual is female. The condition is known as Turner’s Syndrome, and approximately 1 in 2,500 women have it, according to the Turner’s Syndrome Society FAQ at http://www.turner-syndrome-us.org/faqs.htm

ben

Oops…retracting half of previous post. Thanks, heretic. I gather I misunderstood the X vs XX thing.

I worked with parthenogenic turkeys at the Beltsville Research Center of USDA in the 1950’s. A problem with reproducing turkeys by this method is that all the offspring are male, not female as in the case of humans. Another problem is that the little buggers are extremely fragile, due to genetic problems and rarely and with much difficulty could they be raised to adulthood.

By any chance were the genetic problems related to those in the New Scientist article?

Where a Red Queen scenario resulted in a balance between the females suppressing growth, with male genes promoting it?

In the case of turkeys, or any bird for that matter, the situation is the opposite of the mammals. I’m not sure I can remember the terminology correctly. A homozygote, a same chromosone (XX) fertilized egg, will create a female in mammals, but a male in birds. The heterozygote(XY) is male in mammals, female in birds. Though, I think biologists use different letters when talking about bird genes.

So I guess female birds are the one inheriting colour-blindness and hemophilia. :slight_smile:


Only humans commit inhuman acts.