First confirmed hatchings of two California condor chicks from unfertilized eggs | Hacker News Reader

First confirmed hatchings of two California condor chicks from unfertilized eggs

stories.sandiegozoo.org

180 pointsdsr1299 comments

This article has a bit more detail and describes the health issues these birds experienced

https://www.theatlantic.com/science/archive/2021/10/californ...

"both of the condors did have some documented health issues. SB260, a male hatched at the San Diego Zoo Safari Park in 2001, died two years later after being released into the wild—he was always small and did not integrate well with the wild birds. SB517, a male hatched at Los Angeles Zoo in 2009, had a curved spine and trouble walking. He was never released into the wild and died in captivity at about age eight."

So in birds, sex chromosome arrangement is a reverse of what we have in humans. Their males are ZZ and the female is ZW. Which is why only males appear from this parthenogenesis.

> Which is why only males appear from this parthenogenesis

Could you explain the mechanism? If the female has both chromosomes, why couldn't it produce offspring with both?

The mostly likely path to parthenogenesis in a ZW female is making ZZ and WW offspring, and the WW is usually not viable.

https://en.wikipedia.org/wiki/Parthenogenesis#Sex_of_the_off...

The mechanisms of parthonenogensis aren't fully characterized, but at a high level, it occurs in a secondary oocyte during meiosis II -- the oocyte only starts out with a Z or W chromosome.

It's perhaps best shown in this figure: https://rep.bioscientifica.com/view/journals/rep/155/6/image...

(Via this paper: https://pubmed.ncbi.nlm.nih.gov/29559496/)

If the females are ZW, why can't they make WW or ZW?

ZW is less likely because normally parthenogenesis starts with a haploid egg cell (Z or W) that undergoes meiosis alone, copying its own chromosomes - becoming ZZ if it started as Z and WW if it started as W. WW is normally not viable, just like YY in mammals, so the most likely case of parthenogenesis by far is ZZ, male.

Thank you!

So in this case, the ZZ offspring is a genetic clone of its grandfather? That's the only sense I can make of it.

No, wait, half clone. Yup, I'm fully confused by this turn of events.

It's a "clone" of half of the mother's DNA. The mother had random inheritance from its parents. So it's not a clone of the grandparents, but it's a copy of (half of the) mix that the mother had.

No, it's more like an extreme case of in-breeding.

On the other hand, if a mammal were to produce a viable fertile offspring through parthenogenesis, then that offspring would be a clone of it's mother.

Meant to say: mammal mother produces a viable offspring through parthenogenesis, which in mammals would be XX, a daughter, an in-bred individual. Now, if that daughter produces another daughter through parthenogenesis, then this second generation of parthenogenesis individual would be a clone of the first generation daughter.

Right.

From my very shallow understanding:

- The fact that females are defined by unmatched sex chromosomes rather than matched ones means that in haploid parthenogenesis (a split and rejoining of a single half of a genome, rather than fertilisation by male and female sex cells), the resultant sex cells are either ZZ (vialble male) or WW (nonviable "super-female").

- Parthenogenesis in mammals on a similar basis isn't possible as the umatched chromsome is found in males (giving a viable XX female) ... but without an ovum or womb. A self-replicating female egg would be XX.[1] There's ... some research into parthenogenesis in mammals, and at least one apparent observed instance.[2]

- In the case of Avian or similarly Z/W species, parthogenesis is a potentially viable option for resuming sexual reproduction of a population in which all males have been lost. For mammallian populations, not so much. In any case, there'd likely be an extreme genetic bottleneck.

________________________________

Notes:

1. Religious implications for spontaneous mammalian parthogenesis resulting in male offspring are left ... undiscussed.

2. See Google Scholar for a literature overview: https://scholar.google.com/scholar?hl=en&as_sdt=7%2C39&q=par...

Was Jurassic park wrong then?

I was reading the wikipedia article, and this line "Use of an electrical or chemical stimulus can produce the beginning of the process of parthenogenesis in the asexual development of viable offspring.[97]"

Really stood out to me. It seems like there are stimuli that can trigger this process (either naturally or induced).

I wonder if learning about those pathways/approaches/(APIs?) can unlock manual triggering of other behaviors (like telling an Immune system to calm down during allergies / cytokine storm, or spurring or stopping growth of certain cells...)

Apologies for the low-effort comment, but this really freaks me out. I had no idea birds could reproduce asexually! That's crazy!

Feels like an unanswerable question, but: could we ever see something like this in mammals? A virgin birth, for lack of a better phrase?

It's been proposed that artificial sperm could be fashioned from a woman's DNA. I suppose a child born from both a mothers egg and "sperm" could be considered a self made clone.

According to wikipedia, it does occasionally happen that a human egg cell undergoes parthenogenesis and starts developing, but as far as has been recorded, the fetus is never viable and is usually regarded as a type of tumor called a teratoma; occasionally, this does lead to some fetus-like shape of the tumor, in which case it is known as a fetiform teratoma.

Interestingly, there are a handful of cases of functioning human individuals who have cell lines in their body that are the result of parthenogenesis: an egg cell starts dividing by itself, and is fertilized only after this process has started. Next, the feritilized cell line develops normally, while the unfertilized cell line keeps developing as well but in limited ways - in the first known case, the white blood cells of a boy were found to be entirely derived from his mother, while other cell lines were normal XY cells inherited from both parents.

https://en.wikipedia.org/wiki/Parthenogenesis#Humans

Also found a medical article describing a clinical case and also making the parthenogenesis link.

Caution when clicking, the article also contains some photos of the teratoma, which are slightly disturbing!

https://meridian.allenpress.com/aplm/article/130/10/1552/459...

> could we ever

"ever" is pretty open-ended. In principle, it's possible.

The most obvious problem is that if the maternal genes include any that are homozygous lethal or homozygous impaired, the embryo is also a no-go. This is in principle fixable using genetic editing using known techniques.

The more subtle biggest obstacles that I can think of of the top of my head is DNA methylation-related defects. If you are interested in a "quick soundbite example" of why this is important, I recommend reading https://en.wikipedia.org/wiki/Prader%E2%80%93Willi_syndrome (note the 25% of cases when this is what happens when there are by bad luck two maternal copies - and zero paternal copies - of ONE chromosome, similarly Angelman's syndrome); all chromosomes -- or any other chromosome, it appears -- is embryonic lethal in humans.

The underlying mechanism is: https://en.wikipedia.org/wiki/Genomic_imprinting

There is not any known way to effectively edit DNA methylation. It doesn't take star-trek level phlebotonium to get there (it's physically possible, just not with current levels of tech).

There's a great passage about this in Genome by Matt Ridley, which is a great book for anyone interested. In mammals both the male and female gametes imprint their DNA in their sex cells to repress certain genes, if you combine two generic sequences from two males (with no modification) the zygote forms with no brain and too much placenta and dies soon after. If you do the reverse with females, you wind up with a oversized head and no placenta. The working theory is embryonic development is a competitive environment, where males want the best for their offspring at the expense of the female host, and the females 'fight' back by limiting the amount of resources the child has. it's only been recently we've had the technology to remove the epigenetic markers from DNA sequences to allow combinations of same sex strands.

> Feels like an unanswerable question, but: could we ever see something like this in mammals? A virgin birth, for lack of a better phrase?

The question is easy to answer. Yes, this is a development that shows up from time to time. Species displaying only asexual reproduction all tend to be evolutionarily young, which implies that adopting the strategy rapidly leads to extinction, but it has short-term benefits which mean that there's usually something around trying it out. (And then there are species with obligatory parthenogenesis and also obligatory sexual reproduction, like aphids, which don't experience the problems that pure-cloning species do.)

By way of examples of sexually-reproducing species shifting to parthenogenesis, there is a species of lizard that can only reproduce that way. We can be certain they originally reproduced sexually since they still engage in a (pointless) simulation of copulation.

Wow! Do you know what the lizard species is called? I would love to read more on that.

https://en.wikipedia.org/wiki/New_Mexico_whiptail

I can't explain how stoked I am about this, I was in SanDiego when they were on the verge of extinction, even got the chance to go behind the scenes for the original breeding program. Knowing nature refuses to let them fade away even without our intervention is epicly awesome news.

If you have a chance, check out the breeding program at The Peregrine Fund near Boise, ID. We were able to stop there on a road trip and it was really remarkable how many breeding pairs they have. As a fan of birds of prey they also have several eagle and hawk varieties and breed a significant number of Peregrine falcons as well!

https://www.peregrinefund.org/visit

Unfortunately both of the condors did have some documented health issues. SB260, a male hatched at the San Diego Zoo Safari Park in 2001, died two years later after being released into the wild—he was always small and did not integrate well with the wild birds. SB517, a male hatched at Los Angeles Zoo in 2009, had a curved spine and trouble walking. He was never released into the wild and died in captivity at about age eight.

https://www.theatlantic.com/science/archive/2021/10/californ...

For those thinking "Dupe", this specific submission seems to have hit the 2nd chance queue, as the item was submitted 2 days ago. Meaning it's not actually a duplicate.

Algolia shows the original submission date, at least for now:

https://hn.algolia.com/?dateRange=pastMonth&page=0&prefix=fa...

It appears there was a related story though: https://news.ycombinator.com/item?id=29070133

I tend to discount discussions below a certain threshold.

(What threshold is hard to say, though probably in the 20--40 range. Of course, interesting and salient comments can occur at any level. Perhaps more concentrated in smaller discussions.)

Do condors generally have one egg at a time or were there other eggs hatched at the same time with a male parent? Do they think the two bird's early deaths were related to their parthenogenesis, and did the 8 year old one parent any children? On that note, what was the gender of the unfertilized chicks?

Recent and related:

The first report of asexual reproduction in California condors - https://news.ycombinator.com/item?id=29050435 - Oct 2021 (16 comments)

Can someone ELI5 how this works and why it is happening now?

So this is essentially Condors cloning themselves.

How does it work? I don't know how condors regulate their internal functions. As a human, I can control my muscles and my breathing, but I can't control, say, my digestion, my liver, my heart beat (except indirectly by either relaxing or doing stressful activities). How would a bird "flip the switch" and initiate asexual reproduction?

How can anyone answer a question about the subjective experience of a bird? :)

If I had to guess, it could be a subconscious switch happening based on environmental and mood factors, similiar to how human pregnancies can miscarry in times of extreme stress.

Lack of chemicals from the male to inhibit the process probably

Interestingly, in this case males were in fact available - it just seems based on genetic studies that they didn't participate in these particular chicks (the mothers went on to have other chicks through normal reproduction).

I don't know the answers to your questions, but parthenogenesis is confirmed to happen in other organisms. So I presume it could follow an analogous mechanism with condors.

I think it is far more likely the researchers screwed up here.

Parthenogenesis is more common in the animal kingdom than you might expect.

At least part time parthenogenesis. Eukaryotic species sometimes go all in on asexual reproduction but almost always die out in a few million years due to not being able to evolve along with changing conditions.

That's nuts

Quite the insult to the male condors. They were housed with the females, and but the females biologically opted for cloning themselves instead.

[Condorman] did poorly at the box office. Disney reportedly lost $9.5 million on the picture. The disappointing financial returns from Condorman, along with three other flop films, contributed to Disney's poor financial performance in 1981.

https://en.wikipedia.org/wiki/Condorman

Aside for the title "Condorman", how is this movie relevant for the article we are discussing?

Incorrect film reference. Below is a correct film reference quote for this article.

Mr. Liggett: Now there seems to be a lot of confusion on this next question: asexual reproduction. Could someone tell me please who first suggested the idea of reproduction without sex? [1]

David Lightman: Ah-heh. [whispers something to a classmate]

Jennifer: [overhearing, Jennifer starts to laugh]

Mr. Liggett: [turns around and sees Jennifer giggling] Miss Mack! What is so amusing?

Jennifer: I... [Jennifer breaks up into laughter again and turns to look at David, who puts on a show of mock innocence]

Mr. Liggett: Alright, Lightman. Maybe you could tell us who first suggested the idea of reproduction without sex.

David Lightman: Umm... Your wife? [the class erupts into laughter]

Mr. Liggett: [pointing to the door] Get out, Lightman. Get out.

[0] https://www.youtube.com/watch?v=LwDbgE54QYE&t=1m18s

[1] https://en.wikipedia.org/wiki/Charles_Bonnet

Male clones of themselves even!

Hmm, all birds are dinosaurs. It’s been a long time since I last saw Jurassic Park, but wasn’t something like this a plot line in the film?

Yes, it is exactly this plot line for how the dinosaurs were able to reproduce. All the animals were selected to be female to prevent natural reproduction.

There is, but if I remember correctly this was due to using frog DNA to fill in missing DNA gaps.

Same explanation's used in the novel, too.

The plotline there, as far as I remember, was that bullfrog DNA meant that some female dinosaurs could actually morph to become male and reproduce with the females (this is something that happens in some fish, amphibians, and even reptiles, where sex is not genetically determined).

Grouper are all born females but they have both male/female organs at birth. The largest females will turn into males.

Correct, and they had a designed lysine deficiency that was supposed to make them reliant on human-given dietary supplements to live. By consuming lysine-rich foods they were able to live without humans and some gradually changed sex to become male, leading to viable reproductive groups on the island.

Somewhat. In both cases, females were able to self-reproduce. In the film, females switched to male to fertilize. In the condors case, eggs developed without fertilization from males who were available.

Condors. Condors are on the verge of extinction. If I was to create a flock of condors on this island, you wouldn't have anything to say.

Also:

> However, in a surprising twist, they found that neither bird was genetically related to a male—meaning both chicks were biologically fatherless; and accounted for the first two instances of asexual reproduction, or parthenogenesis, to be confirmed in the California condor species.

Life, uh, finds a way.

Damn, you beat me to it. :)

well, there it is.

Really? No “life will find a way?” memes or quotes?

I made the joke but got downvoted :(

Many would argue this already occurred with Jesus, born from the virgin Mary.

Most Christians believe that that was not some biological process, but a true miracle where God himself bestowed this child on Mary. It would be technically correct that this was parthenogenesis, but it is a completely different... mechanism.

Most non-Christians, even if they believe Jesus was a true historical figure, do not believe that his mother was a virgin.

this is complicated, nuanced and not literal; it is a typical thing for critics to latch on to, so let's be wise-cautious with the exposition here at YNews, please

Absolutely. I wasn't trying to criticize anyone's beliefs, and I hope I didn't come across as such, and sincerely apologize if it did.

My only point was exactly that it's not a great idea to take a religious experience and analyze it as an example of a basic biological phenomenon.

'this is complicated, nuanced and not literal' - arn't most things though? At least the person you are replying to started their comment with a weasel word - you're the one making the categorical statement about whether it is literal.

Miracles are absolutely (supposed to be) literal. It's a requirement for Sainthood, for example.

> be wise-cautious with the exposition here at YNews, please

One would think that YNews would be the most appropriate place for questioning blind faith in absurd claims.

Not Christian, but as my Rabbi used to say: "When God created the earth 5782 years ago (give or take a few billion years),"

Mel Brooks?

It would not shock me in the slightest if that's where he got it.

> Most Christians believe that

Do you have any sort of statistics to back this up? A survey of some kind? From my own experience, most people who are Christian subscribe to the lifestyle and teachings, but do not accept 100% of the bible as truth.

It's... at least the official doctrine of most Christian churches, yeah, and that's usually held as a particularly important point. Catholics, certainly, and they're rather numerous. It is possible that many, or even most, Christians disagree with tenets of faith that their churches hold to be absolutely vital and indispensable, I suppose.

[EDIT] It's part of the Nicene Creed, even. I think it's fair to say that if most church-goers at most Christian churches told a priest or pastor that they didn't believe that God miracle'd a baby into the Virgin Mary, it would, at the very least, give the priest or pastor a frowny face and/or evoke a "wait... what exactly do you think we're up to, here?" reaction.

Anecdotal, but I've never met or even heard of a Christian who believed in the virgin birth but thought it was the result of a natural process. Are there any examples of that you're aware of?

There was a Discovery channel documentary in the 2000s that tried to give "scientific" explanations for the miracles in Christ's life. Parthenogenesis was the theory they advanced instead of divine conception.

Sure, that sounds interesting and unsurprising. But was any of it believed by Christians?

I don't have data for the whole world, but at least in the USA, most Christians (and the majority of Americans) believe in the virgin birth of Jesus Christ [0].

[0] https://www.pewforum.org/2017/12/12/americans-say-religious-...

> Do you have any sort of statistics to back this up? A survey of some kind?

The virgin birth of Jesus is an article of faith and dogma for Catholicism, itself a major branch of Christianity.

How about the fact that over a billion people are members of the Catholic Church? The membership of which requires believing quite a bit of Biblical literalism.

Tbh that whole argument is always kinda weird: If those people don't believe in the whole thing, why are they members in a church about it? That's pretty much the only statistic you need.

[0] https://www.bbc.com/news/world-21443313

>If those people don't believe in the whole thing, why are they members in a church about it?

Usually they inherit the religion from their parents. They grow up with the church as family so even if they don't believe in the tenets/beliefs they still participate.

A lot of people are religious/affiliated with a specific religion due to inertia. Church attendance was compulsory for a lot of history. There are not a whole lot of people converting to catholicism/protestantism/judaism from other religions. I only very recently found out the technical differences between lutheranism and methodism, largely details around how/why baptism and taking sacrament from what I can tell, but growing up, we always went to one church and not the other even though nobody could tell me why.

> Most Christians believe that that was not some biological process, but a true miracle where God himself bestowed this child on Mary.

Most Christians that have spent the time to consider what it means for God to manifest a miracle fairly explicitly accept that that necessarily involves some physical sequence of events, potentially leveraging underlying capacities which in time and space predate the event which God, being all-knowing and existing outside of time and space, may have created for the express purpose of that specific miracle.

And most of the rest of Christians would probably dismiss the mechanical question as irrelevant for miracles, preferring to ask “why” rather than “how”.

> Most Christians that have spent the time to consider what it means for God to manifest a miracle fairly explicitly accept that that necessarily involves some physical sequence of events

That hasn't been my experience. I don't know about "most" Christians -- I wouldn't dare presume to speak for anyone in the US, for example -- but every Catholic I've spoken with (I live in a majorly Catholic country) believes in the entirely miraculous virgin birth of Jesus.

I think the phrasing "most Christians that have spent the time to consider [...]" is unfortunate; it reads like "every Christian which believes [this thing] believes [this thing]". Or it makes Christians who do believe in the miraculous birth without a prior physical setup to be somehow less thinking Christians.

Do note I'm an atheist myself so I certainly don't believe in miracles, either direct or indirect; I've no dog in this race.

> but every Catholic I've spoken with (I live in a majorly Catholic country) believes in the entirely miraculous virgin birth of Jesus.

Sure. I’m a Catholic and I believe that.

It’s also a non-explanation that doesn't actually rule out any particular physical process occurring as part of the manifestation of the miracle.

Other than things like the routine transubstantiation of the elements of the eucharist, where a defined part of the miracle is the absence of any physical manifestation of it occurring [0], that's pretty typical of miracles.

[0] Why doesn't the bread and wine that miraculously becomes the body and blood of Christ taste like flesh and blood? Well, because it miraculously also retains all the physical properties of bread and wine...

> Why doesn't the bread and wine that miraculously becomes the body and blood of Christ taste like flesh and blood? Well, because it miraculously also retains all the physical properties of bread and wine...

I'm not a Catholic, but I figured that most people interpreted the bread and wine as symbolic.

lots of stories in religion are not literal -- they are presented as undeniable Truth to quash low-level arguements

Many would argue

Paul's Letter to the Internetans: Chapter 1, Verse 1.

Paul's Letter contains this warning: "[And Thou Shalt Add a Citation, Lest Your Claim Be Purged From Internetan Records]"

I mean, I'm not sure that _many_ would argue that. Most people would either take the view that Jesus had a human father, or that a miracle was involved. If nothing else, if he'd come about by this pathway, he'd be XX, which you'd think would have merited a mention in the Bible.

(It isn't totally unknown for XX people to be phenotypically male, and it'd fit with him having no kids, but really this seems like a needlessly complicated backstory for Jesus.)

Please don't take HN threads on religious tangents. It's off topic and just leads to religious flamewars.

We detached this subthread from https://news.ycombinator.com/item?id=29068477.

No one argues that the Immaculate Conception is parthenogenesis. It could not possibly have been, because if it had, either Jesus would have been Jesusa, or Mary was hermaphroditic and Jesus her genetic clone. Since we know neither of these explanations is credible, it had to be miracle birth. When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.

Now with Horace and Isis it's quite different. Isis was a virgin and Horace was a falcon, so I'm really not sure how that worked.

Reply on news.ycombinator.com