June 13, 2017 12:59 PM   Subscribe

Three father species, one hybrid species: The all-female Ambystoma salamander hybrid lineage (6 Ma and counting!) uses equal parts of the genetics from three different sexually-reproducing Ambystoma species. Each hybrid mates with (at least?) three fathers of the different species to gather sperm and has only female offspring.
posted by clew (11 comments total) 30 users marked this as a favorite
Man. Evolution is so freaking weird.
posted by tavella at 1:10 PM on June 13, 2017 [1 favorite]

I mean, that sounds like a wacky sexual reproduction method out of a science fiction novel. A lineage of female aliens who reproduce via genetic banks.
posted by tavella at 1:12 PM on June 13, 2017 [3 favorites]

That was probably the most uncomfortable episode of the X-Files.
posted by Halloween Jack at 1:30 PM on June 13, 2017

Another (??) female Ambystoma lineage? species? mostly reproduces by cloning, but occasionally gets some variety 'by "borrowing" sperm left behind on leaves and twigs'. (And is larger, and regrows its tail faster, than the sexual species.)
posted by clew at 1:41 PM on June 13, 2017 [5 favorites]

Awesome news! Whenever anyone asks me to explain why the Andorian species in Star Trek has four sexes, I can refer to this fact.
posted by the matching mole at 2:06 PM on June 13, 2017 [2 favorites]

The headline of the article, the url and the first sentence all use the word promiscuous. This salamander is the exact opposite of the definition promiscuous.
posted by Keith Talent at 2:34 PM on June 13, 2017 [1 favorite]

Turns out I owe the makers of Mass Effect an apology. Asari reproduction is more realistic than I had given them credit for.
posted by ckape at 3:10 PM on June 13, 2017 [1 favorite]

> I can refer to this fact.

You know who else had four sexes!?
posted by I-Write-Essays at 4:02 PM on June 13, 2017 [8 favorites]

Goodness, I-Write-Essays, that's a combination of scholarship and elegy like The Decipherment of Linear B.
posted by clew at 5:44 PM on June 13, 2017 [2 favorites]

I saw this earlier and was thinking of posting it, but I'm still trying to wrap my head around it. Here is the original paper. A couple of highlights not covered in the summary:
The rate of genome introgression from sexual Ambystoma males into the unisexual lineage is estimated to be ~0.2% genomes/generation
So it sounds like they don't mate every time - just occasionally. 1 in every 500 or so per generation takes a holiday from Crone Island and then comes back.

This paper was mostly about gene expression, and the quotes in the posted summary about the advantages of balance sound to me like they're maybe not right. (?) Most of the similar polyploid species studied so far silence their genes in an unbalanced way; this species is special because it has "an unusual level of genome balance". That doesn't appear to be an advantage for most polyploid species, based on how few of them do it. (However, this lineage has lasted much longer than typical unisexual lineages, so maybe that's the advantage of balance that they're proposing?)

Based on the citations, it looks like JP Bogart is the resident Mr. Salamander. In this paper, the term kleptogenesis is proposed and the male salamanders involved are pictured. There's a fair range in salamander size. This paper talks about the complicated outcomes of kleptogenesis:
The acquired sperm may only serve to stimulate unreduced eggs to develop (as in gynogenesis) but a male’s genome can be incorporated to replace an existing genome or to increase the ploidy level in unisexual offspring. Kleptogenesis has resulted in the establishment of diploid, triploid, tetraploid and pentaploid unisexuals possessing more than 20 different nuclear genomic combinations or biotypes.
I've read in a couple of places that polyploidy is much more common in plants because animals have more complicated developmental pathways which are too easily thrown into off-course dead ends. Add a whole second genome, and you're more likely to get a miscarriage or a dead egg than a successful offspring. Salamanders seem to be immune to that problem. Pentaploid? Why not! Our development pathways are flexible enough to regrow a limb, so why not just throw an extra genome or two in there while you're at it, too?
posted by clawsoon at 7:29 PM on June 13, 2017 [4 favorites]

I-Write-Essays: You know who else had four sexes!?

"'Elaina was the best bird masturbator I ever met,' Gonser says."

Rule 34 activated.
posted by clawsoon at 7:36 PM on June 13, 2017 [2 favorites]

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