Talk:Outbreeding depression

Racism

This page, along with miscegenation, is the frequent target of edits that attempt to use questionable reports, or misinterpretation of reports, to promote racist ideologies and/or anti-interracial propaganda, as the page history shows. Reports about the foetal health and/or metrical measurements of interracial children or adults should not be added to this page. Hunan201p (talk) 00:56, 25 December 2019 (UTC)

In other words, dont mention humans in this article at all because that's not PC Aube123 (talk) 22:02, 23 September 2020 (UTC)

Of course humans can be mentioned, but if the paper doesn't involve outbreeding depression, it probably shouldn't be included. I agree with Hunan201p (talk); I believe Aube123 (talk) is misinterpreting what he is saying. MathIsMusic (talk) 01:28, 22 April 2021 (UTC)

Which "in humans" things to include/what is in good faith

There is a slight issue here. Obviously, outbreeding depression is a biological concept, and so it applies to all organisms, including humans. There are also legitimate publications and discussions about outbreeding depression in humans. However, there are racist motivations to overly apply outbreeding depression to humans. I've gone through the edit history and I'll compile claims/sources that were in previous "in humans" sections (these sections go back to the creation of the page) and list them below, where we can have a discussion about if it would be best to include them. I'll give my opinion and it would be great if others would chime in. MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Include a thumbnail involving humans as the example? https://commons.wikimedia.org/wiki/File:Total_Number_of_Grandchildren_and_Relatedness_of_Grandparents.png

No, this seems like it is focusing too much on humans. Most discussion of outbreeding depression involves conservation efforts for non-human animals, so a human-involved thumbnail is unusual and unnecessary, and may be in bad faith. However, there should be a quality non-human replacement for the thumbnail.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Include "miscegenation" under see also?

No, that appears to be in bad faith. To my knowledge there is no source that links that term with outbreeding depression.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Outbreeding depression as a reason why "fertility often increases with kinship?" https://science.sciencemag.org/content/322/5908/1634.2

I think so. This is referenced and is relevant.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Include "ADAMTS13 gene?" https://ashpublications.org/blood/article/110/11/277/74483/The-ADAMTS13-Gene-as-the-Immunological-Culprit-in

Yes, under some circumstances. This is the first publication on a specific instance of outbreeding depression in humans, which makes it relevant in my opinion. However, the wording must careful and very neutral.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Include HapK gene? https://www.nature.com/articles/ng1692

Soft yes. I went from no, to maybe, to yes on this one. On one hand, it should be added due to very large clinical relevance. On the other hand, this sometimes seems to have been added in what I'll call "less-than-good-faith." Furthermore, the paper isn't really about outbreeding depression; it's about something which results from instances of outbreeding depression. However, so are many articles used for plants in animals, and the authors specifically linked this result to the mechanism of outbreeding depression in subsequent media releases. What made me change my mind was that this result has been discussed in the media and there were specific medications made for African-Americans as a direct result of this study. However, if this is included, it must be done with an exceedingly neutral point of view.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

After considering that [[WP::SYNTH]] is original research by synthesis (not just any synthesis, WP:NOTJUSTANYSYNTH) and that WP:SYNTH is not a policy itself, but of the larger policy of no original research, I don't think my previous point about "not really being about outbreeding depression" is valid. The Nature article is an obvious example of outbreeding depression (it just doesn't mention it by name). For example, I could use a silver birch as an example of a tree on a Wikipedia article about trees even if a publication doesn't explicitly state that the silver birch is a tree, because the definition of "tree" obviously applies to the silver birch.MathIsMusic (talk) 04:06, 23 April 2021 (UTC)

Include this link (about the above article)? https://www.nytimes.com/2005/11/11/health/genetic-find-stirs-debate-on-racebased-medicine.html

I think this link can be included for perspective if needed (Generalrelative (talk) brought up the point that the author of this article may be biased, so that should be considered). However, it should not be used in a biased and skewed manner such as found here: https://wiki.riteme.site/w/index.php?title=Outbreeding_depression&oldid=28868744.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Include pregnancy risks of Asian/White couples? (no link, see https://wiki.riteme.site/w/index.php?title=Outbreeding_depression&oldid=931718946)

No, because there's no evidence to say that this results from outbreeding depression. This could be due to any number of things. Since I don't believe there is any publication or secondary source linking this to outbreeding depression, this should not be added.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Include "black and white couples face higher odds of prematurity and low birth weight?" (no link, see https://wiki.riteme.site/w/index.php?title=Outbreeding_depression&oldid=931718946)

No, for the same reasons as above (there's no evidence...).MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Include "adverse birth outcomes" for b/w couples?

No, for the same reason as above. If the source doesn't clearly link the outcome to the genetics/reproduction, it probably shouldn't be added.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

Include outbreeding depression "is also observed in human populations, where interracial breeding results in an average 43% increase in still births"? https://obgyn.onlinelibrary.wiley.com/doi/full/10.1111/j.1600-0412.2012.01501.x

No, because the source doesn't say that the cause is genetic, and doesn't even attempt to establish causality at all.MathIsMusic (talk) 02:57, 22 April 2021 (UTC)

@MathIsMusic: Thanks for your hard work here. This is really thoughtful stuff. That said, I'm not seeing the kind of references I'd want to see to include a section which suggests that there is such a thing as outbreeding depression in humans. Notably we would need WP:SECONDARY sources. Sometimes primary sources can be useful as a supplement, especially when the overall science is clear, and the comment published in Science is on its own quite interesting, but for a topic as controversial as outbreeding depression in humans we would need secondary sources stating that there is broad agreement that it even exists. Indeed, the 2007 article in Blood states in its title that it represents the "First Evidence of Genetic Out-Breeding Depression in Humans". If it's the first evidence, either it represents an outlier or there should be additional results by now, and those results should have been subjected to some sort of meta-analysis or at least systematic review. These would be the type of sources that we could base a section on. Otherwise I would object to giving credence to the idea that outbreeding depression is known to occur in humans. We are, after all, a remarkably genetically homogenous species. Generalrelative (talk) 03:45, 22 April 2021 (UTC)

Also, you asked about including an op-ed by discredited science journalist Nicholas Wade. Hard no from me on that one. Generalrelative (talk) 03:54, 22 April 2021 (UTC)

The Nature article is indeed not about outbreeding depression so including it here would be WP:SYNTH. Generalrelative (talk) 04:03, 22 April 2021 (UTC)

@Generalrelative: Those are good points. Although other places on this page only list primary sources, there's more of a burden to have better sources for potentially sensitive issues like this. It would be great to add secondary sources if any of the potential edits were added. However, after reading WP:SECONDARY and WP:PRIMARY, Wikipedia allows and encourages primary sources if they are used carefully and properly. Therefore, primary sources can be added if and only if:

1. It is used to make straightforward, descriptive statements of facts that can be easily verified

2. The editor must not analyze, evaluate, interpret, or synthesize material found in the primary source, and

3. The editor must word the primary source in a way as to not a potential "outlier" as fact. I.e., say "X et al. suggest 'A' may be evidence for 'B,'" instead of something like "D causes E."

This way, an editor can add relevant information. After all, the entire "In Plants" section is based on one primary source. Other areas on this page follow this pattern of being heavily/entirely based on primary sources. This is just due to the fact that outbreeding depression isn't a huge topic; no journalist really wants to write a secondary article about it. For example, the Wikipedia page for AFAP1L2 consists largely of primary sources because it simply isn't that exciting of a topic for loads of people to write about.

I understand the (very valid) concern, but the concern can be addressed through careful wording and adding secondary secondary sources when possible.MathIsMusic (talk) 04:21, 22 April 2021 (UTC)

Thanks for the thoughtful engagement. And you're right that the citations in this article leave a lot to be desired. But that is often the case on Wikipedia. The key difference is that the existence of outbreeding depression in other species is not controversial. It would be nice if someone would do the work of citing secondary sources, but no one is in doubt that they exist. Whereas this is not at all the case with regard to humans. Again, this shouldn't be surprising since we are a much more genetically homogenous species than most. As far as I can tell, the idea of outbreeding depression in humans, or at east the idea that evidence for it currently exists, falls under Wikipedia's definition of WP:FRINGE and should therefore be treated with extra caution. If you disagree, or if for any other reason you'd like to bring more editors into this discussion, you might consider posting at Wikipedia:Fringe theories/Noticeboard. Generalrelative (talk) 04:40, 22 April 2021 (UTC)

Oh, and to be clear: I'm not talking about secondary sources by journalists. What we'd be looking for here is meta-analyses or systematic reviews by scientists. A WP:TERTIARY source like a textbook could work too. The reason why I don't think you will find these is that, as far as I understand, it is obvious to most geneticists that extant human populations are too genetically similar for outbreeding depression to be plausible. Generalrelative (talk) 04:46, 22 April 2021 (UTC)

I'm not sure that outbreeding depression in humans is controversial. There are not meta-analyses or systematic reviews on the topic at all, so we can't look towards these types of sources to determine consensus. Anyway, let's say that humans are more homogenous than most species. That wouldn't negate outbreeding depression, it would just decrease the effects of outbreeding depression. In other words, it would make it less of a concern, but wouldn't make it non-existent. Outbreeding depression can exist even within a homogenous species. A tertiary source on this topic describes "Natural selection can promote rapid development of reproductive isolation, which results in outbreeding depression." It also listed "Populations separated [by] >20 generations" as a criteria to indicate if outbreeding depression may have occurred. Therefore, outbreeding depression can happen in populations that aren't extremely genetically separate. Other criteria: if the populations "have been isolated for 500 years or longer, or have been living in significantly differing environments for more than 20 generations, there is a modest to high risk of outbreeding depression if the populations are crossed." The same source states that outbreeding depression is less common in large mammals, which probably contributes to why humans are not included in most tertiary sources (the proposed examples of human outbreeding depression are just one small example out of millions of species). I don't mean to argue that outbreeding depression actually exists in humans; I just mean to state that outbreeding depression can occur within a homogenous species. MathIsMusic (talk) 06:12, 22 April 2021 (UTC)

On the issue of fringe, Wikipedia lists "peer-reviewed journals" among "the most reliable sources," so I don't believe this falls under fringe. Of course not every article will meet this standard, but if there are solid articles from non-controversial authors, fringe shouldn't be a reason to not include them especially if there is no argument within the literature. (By no argument, I mean there is no scientific debate about whether outbreeding depression occurs in humans: it is either stated a priori or the subject is not mentioned at all). If a peer-reviewed has no issues, then I don't see why it would be classified as fringe. Even "a theory that is not broadly supported by scholarship" should be included as long as it is not given "undue weight" WP:FRINGE. Regardless of if anything is fringe or not, I agree we should treat this with extra caution, and hopefully other users will weigh in with their perspective. MathIsMusic (talk) 06:11, 22 April 2021 (UTC)

I'll just reply one more time to say:

1) You may be right about outbeeding depression in general. I'll leave off speculating, based on my own understanding, as to why we see so few serious scientists discussing the possibility of outbreeding depression in humans.

2) I'm afraid that your reading of WP:FRINGE doesn't square with my own. The comment in Science which you linked above and the article in Blood both represent what is called an "alternative theoretical formulation". In this case, they are an "alternative" to the null hypothesis. That doesn't make them any less fringe, nor does the fact that they appear (sporadically) in peer-reviewed journals. What makes them fringe is the fact that there is not yet widespread, mainstream scientific buy-in that they are reporting on a real thing. And yes, that is indeed a very solid reason not to include them. All that said, I will once again suggest bringing this to Wikipedia:Fringe theories/Noticeboard if you disagree. This talk page on its own is unlikely to get much traffic. But in any case, let's wait for others to weigh in rather than argue back and forth between the two of us. Best, Generalrelative (talk) 14:58, 22 April 2021 (UTC)

That sounds good. Thanks for the discussion; I'll likely bring this to Wikipedia:Fringe theories/Noticeboard or something akin. I agree on waiting for others to weigh in, but just for the record if anyone else stumbles across this discussion: the alternative hypothesis is the statement that something is occurring, but that statement can be positive (ex. the medication changes disease outcome) or negative (ex. this gene which is usually conserved as absent). In other words, the null hypothesis can be that there is no effect, but it could also be that there is no difference between groups (i.e., no difference between humans and other animals). In regards to the lack of widespread science talk about this topic, that would only apply if there was a stated conflicting view. For example, if Bowen Hutterite Syndrome (a rare disease) is rarely discussed in literature and is left out of reviews/textbooks, that does not mean Bowen Hutterite Syndrome is considered fringe. It cannot "depart significantly from the prevailing view" because there is no stated opposition/prevailing view. However, subjects like autodynamics (https://wiki.riteme.site/wiki/Autodynamics) are considered wp:fringe because they specifically conflict with the mainstream view (general relativity).MathIsMusic (talk) 18:07, 22 April 2021 (UTC)

@MathIsMusic: In response to the comment you've altered above (note that per WP:TALK you need to clearly indicate when you've altered a comment after someone has responded to it. Here's an example of how it's typically done.): I didn't say that Wade "may be biased". I said that he's "discredited". Generalrelative (talk) 04:10, 23 April 2021 (UTC)

Skip the human sources

I was asked to look at the article, a while ago when I was on a wikibreak. Not familiar with the topic since I've been doing human genetics where it's never mentioned. Don't use the ADAMTS13 source, it's not a scientific article. It's a conference abstract, without data (and of course without peer review, there's not even something to review). Some articles do have cited it, but as an allelic dominance effect. The authors' line of reasoning, that ADAMTS13 heterozygosity leads to a stronger immune system which increase the risk of autoimmune disease which is deleterious and therefore outbreeding depression, has two big holes. One is cases with ADAMTS13 homozygous mutant having the disease, which is hard to tell without the data but reads like they had, which means it's just allelic dominance. Another pitfall is to link one disease to alleles reducing fitness, without actually measuring fitness . the immune system does involve itself in other roles than just that one autoimmune disease. The HapK paper isn't about outbreeding depression at all, just some deleterious allele more common in Europeans (there's lots of deleterious alleles among humans, spread out in different patterns geographically...). The "Biracial couples and adverse birth outcomes: a systematic review and meta‐analyses" article isn't about genetics, just about how Blacks are disadvantaged in the US health care system, this kind of environmental factor I've seen specifically pointed out at a US conference. All in all, none of the "in humans" sources hold up. Stick to animals in the article. Narayanese (talk) 10:01, 17 May 2021 (UTC)

References

Simultaneous and contextual fitness + future of the article

The simultaneous issue in the intro paragraph can be explained as the measure of fitness being necessarily contextual; an organism can experience outbreeding depression in one factor and heterosis in another. mules obviously can be completely unfit and also very fit depending on the environs of selection. likewise with phenotypes like skin colour; no notion of genetic fitness is reasonable without context, even for example an animal that auto-aborts before birth could be fit in specific contexts. Fitness doesnt seem to be fantastically defined though.

This nature of fitness should be emphasised to better highlight the biases that plague the topic.

I think it would be a worthwhile project writing this page, Heterosis and Inbreeding depression as a group with reference to each other to fully get through the point of the varying fitness posibilities of hybridisation, as this topic is widely controversial and plagued by layman biases. (The fitness page needs help too imo)

Curiously these three concepts arent internally homologous and three distinct themes appear:

1. adaptive effects (combination of traits producing more or less fitness, eg. skin colour vs sun exposure)

2. metagenetic effects (population fitness/adaptability effects, eg. bottlenecking)

3. non adaptive genetic effects (mismatching traits causing issues, eg. two copies of sickle cell or ploidy splitting)

with each of the three cocnepts having a component of each. there is also the missing concept of "inbreeding vigour" (homo-sis? already in use as a term) but it seems so rare i cant find any examples in literature beyond human agriculture ("open pollinated" being confused for "stable inbred" and being valued for its stability over unstable hybrids).

--OsirusHandle (talk) 14:50, 24 October 2024 (UTC)

Excellent points indeed. About the scarcity of examples of inbreeding vigour: disease resistance in domesticated animals may offer more accessible examples than plants. I've heard this referred to as shedding or purging deleterious alleles, and it can be very marked at an early stage in the genetic trajectory of captive populations, which can be very susceptible to disease. Sminthopsis84 (talk) 20:09, 24 October 2024 (UTC)