All of the parthenogenetic species with which I'm familiar are female. Females, obviously, have all the machinery for reproduction in place, and all they have to replace is the function of one itty-bitty little sperm, while for a male to reproduce without females, he'd have to replace the functions of big, well-stocked eggs and uteruses or whatever equivalent organs the mother of the species has at her disposal. It's hard for males to get around the female contribution to reproduction. At last, though, one species of fire ant has shown a way to do it, not that I'd ever want to go down this particular road.
I'm going to expand on this strange genetic pattern John Wilkins described. First, though, here's a little background on haplodiploid sex determinatiion.
Continue reading "Clone war of the sexes" (on Pharyngula)
9 Comments
Rilke's Grand-daughter · 1 July 2005
I know this is a peculiar comment, but that's really neat!
Henry J · 1 July 2005
Re "All of the parthenogenetic species with which I'm familiar are female."
My first thought was how could they be anything else, but let's see if I can follow the article to find out...
Whoa ... That is weird.
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Re "Fathers can only have daughters, and mothers produce sons without the contribution of a male."
Guess that's one way to maintain the ratio of the sexes in the species?
Wonder if they've done a genetic sequence compare on the two presumed to be separate lineages? If the hypothesis is right, the two should be accumulating totally different sets of mutations since their, uh, "separation".
Henry
Flint · 1 July 2005
Might this unusual approach lead to some good way to target and eliminate fire ants? These beasties aren't perhaps quite as bad as polio, smallpox or leprosy, but they're close.
Joseph O'Donnell · 1 July 2005
Depends, I would definitely say yes. Fireants have already been responsible for driving several species to the brink of extinction and are nasty pieces of work. The US really should be doing more to get rid of them because they are not a desirable invader at all. We as humans won't suffer, but other insect species and perhaps some larger animals definitely will.
SEF · 2 July 2005
"target and eliminate fire ants"
Which species though? If your ones are not the same then it won't help. Unless you are first planning to cause that same act of evolution somehow in all the other species (and you've got to know by now that evolution is likely to resist such an attempt and instead go off in some other direction of its own in response to tinkering).
Hai~Ren · 4 July 2005
Well, if I'm not wrong, the fire ant(s) that cause trouble worldwide and are mentioned so often are _Solenopsis invicta_ and _Solenopsis geminata_. The little fire ants mentioned in this article, _Wasmannia auropunctata_, are widespread introduced pests themselves.
harold · 5 July 2005
I have a question about this, and would be grateful for an answer from anyone.
Haploidy is common in unicellular life (pretty much all prokaryotesa are haploid, although I'm sure someone will remind me of exceptions or complications).
Diploid species like humans and dogs, with long pre-reproductive lives, tend to "need" diversity at alleles, however. There's no such thing as haploidy in those species, obviously, but when a certain threshold of homozygosity at multiple alleles is reached - in isolated human populations with few founders and little immigration, or in strictly bred dogs - the burden of genetic diseases tends to rise.
Haploidy should have a similar effect. Every male ant who has even a single unfavorably mutated allele is in essence a "homozygote" for that allele. Every recessive genetic disease is to a male ant what an X-linked recessive disease is to a male human. One bad allele, and he's toast.
How do haploidy-containing insect populations handle this issue? Remember, they're a lot more like us than they are like bacteria. Is there simply a relatively high death rate during development and ant "childhood" from genetic diseases, for the haploid males? Does anybody know?
Marek14 · 6 July 2005
I think it's basically lots of dying - basically, EVERY allele the male has will be expressed, so if they get a bad recessive one, they are toast.
A nice side-effect is that there is much less risk with inbreeding this way, and many species with haploid males are actually habitually incestuous - one (or a few) males hatch out of a clutch along with large amount of females, mate with them, then die.
SEF · 6 July 2005
Yes, if you haven't invested much effort in making a male ant then it doesn't matter if it dies. Much better to make lots of them and just keep the functional ones with guaranteed good genes in some sense. Partial haploidy could be viewed as a eugenics ploy.