Talk:Inbreeding
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[edit] Westboro Baptist Church
Why was this even included? Westboro Baptist Church
The church group (and alleged cult) Westboro Baptist Church has apparently begun inbreeding, with one of its members, Rachel Phelps, being married to her nephew's brother-in-law, Charles F. Hockenbarger (her newphew, Samuel Phelps-Roper, is married to Charles' sister, Jennifer). Additionaly, though it does not interfere with genetics, Shirley Phelps is married to her step-brother, Brent D. Roper. Long before these marriages took place, residents of Topeka speculated that the church's stringent guidelines against marrying outsiders, coupled with the lack of potential spouses within the group (nearly 90 of the group's 100 members are related through blood or marriage) would lead to eventual inbreeding. It is unknown whether this pattern will continue or, if it does, how extreme the degrees of inbreeding will become.
There is no genetic relationship in the above case. Anything else is speculative. Phelps is married to her adopted brother if you read the article on Roper. Whatever our own feelings about the church, I think that bit doesn't add to the article and wasn't motivated by a desire to improve the article.
Comatose51 18:54, 23 October 2005 (UTC)
[edit] Endogamy merge?
How about merging this article with the endogamy article? Maybe the inclusion of the Ashkenazim, also.
Moved this here.
- Inbreeding also occurs in humans. For example, Japan is one of the most endogenous societies in the world.
It doesn't seem clear to me that 1) Japan is more endogenous than say Iceland and 2) this can be regarded as inbreeding since the rate of genetic and health problems in Japan isn't higher than the rest of the world.
- "one of the most" :teach: 74.225.130.13 23:01, 22 March 2007 (UTC)
I don't care who is singled out but I do need at least one example of it in humans.
From the link I gave:
One of the most endogenous societies in the world, Japan has approved of incestuous marriages in court circles even in historical times.(152) Preferred sibling, cousin, uncle-niece and aunt-nephew marriages have been so extensive that genetics experts have discovered that the inbreeding has affected their size and health.(153) How often this incestuous marriage system occurred in traditional Japan is still largely unexplored. One indication of what is likely to be found is a 1959 study by Kubo showing that there were still rural areas in Japan where fathers married their daughters when the mother had died or was incapacitated, "in accordance with feudal family traditions.(154) Kubo concluded that incest was considered "praiseworthy conduct" in many traditional rural families. In the 36 incest cases he studied in Hiroshima, he found that there was often community moral disapproval of the families who lived in open incestuous marriages, but that the participants themselves did not think of it as immoral. In fact, when the father was unavailable to head the family, his son often took over his role and had sex with his sister in order "to end confusion in the order of the home." Other members of the family accepted this incest as normal.
1) Consider the possibility that you can't find an example because there isn't one.
2) Japan has a population of 150 million. Finding a few dozen or even a few thousand cases of incest isn't near enough to label the population as inbreed.
No way. Incest is very prevalent in Japan. It's a question of finding a population that's inbred.
There should be something about inbreedding depression, and perhaps something about breeding culture with animals, where they recommend an inbreeding coefficient around 1-5% as far as I remember. Outbred isn't always recommended.
This whole paragraph needs rewriting:
- The only really major problem with inbreeding is that two closely related individuals are likely to have very similar genomes, and if one individual has a gene for a given negative trait, then the other is likely to have it as well. It is pretty complex, and I would spew numbers, but I'm sure any reasonably intelligent person can figure it out for themselves with a basic knowledge of Gregor Mendel and his plant breeding experiments. Suffice it to say that a single instance of inbreeding is statistically very unlikely to result in a flawed individual.
-- The Anome 09:09, Jan 26, 2005 (UTC)
[edit] External link
I wonder about the link Consanguinity and Mating. While it's got a lot of historical anecdote, it needs at least some kind of context as it comes from the site for Anthony M. Ludovici: not exactly a mainstream take on the subject!
- I agree, and I've removed it. --Xyzzyplugh 01:00, 13 February 2006 (UTC)
[edit] Jewish Law
In Jewish law it is not incestuous for a man to marry his brother's daughter, but does the same apply to marriages between a man and his sister's daughter? The reason this occurs to me is the definition of a Jew as being a person "with a Jewish mother". This suggests a previous matrilineal kinship system, where those related through the female line might be forbidden to marry, but those related only through the male line were not. Can anyone give further information? Too Old 09:45, 9 January 2006 (UTC)
[edit] Pignatelli case
Erm, not highly relevant to its subheading, since they were not royalty.
Anyway, there have been better examples, for example uncle-niece or aunt-nephew marriages.
- Pignatelli was a case of extraordinary generational differences of descent found in some alliances among royalty and nobility. I can rename the heading. Charles 16:28, 27 April 2006 (UTC)
[edit] Outbreeding
"Outbreeding" is linked in the article, but redirects here! The word is not explained in this article, but one could assume[1] that it is the opposite of inbreeding.
Should
- the link be removed,
- a new article created,
- an inline definition be added,
- or, a link to something similar (i.e. Miscegenation) be inserted?
(No, I'm not bold!) CAD6DEE2E8DAD95A 16:58, 9 May 2006 (UTC)
[edit] Charles & Diana
they are left off the list as is the other royals.. Charles & Diana are 3rd cousins.
- No, they are not. Their closest relationship is of 7th cousins, once removed. It is non-notable as many, many, many people are related to that degree or closer. Charles 16:29, 11 May 2006 (UTC)
[edit] Editing
I've done a fair bit of rearranging and added a small amount of material I think it makes more sense now, and am removing the tag. --Michael Johnson 12:20, 11 July 2006 (UTC)
[edit] POV?
- Intermarriage in European royal families is no longer a problem, due to modern science and our understanding of the negative consequences
Does this sound a little POV to anyone? I understand what they're trying to say, but it sounds a bit off to me.--Stella luna 18:32, 27 July 2006 (UTC)
-
- Yes, it is POV. It is widely assumed, but without any reliable evidence, that intra-marriage among royal families caused genetic "problems", e.g. in King Charles II of Spain and the so-called Habsburg lip. But no one ever cites what precise medical condition caused the problem, nor how it was caused or aggravated by inbreeding (rather than, say, multiple-generation inheritance of a dominant gene) -- and the Habsburg lip is not usually a "problem" at all. Rather, people tend to assume that if a person has an observable defect, and if that person has inbred ancestry, then the deleterious trait must be due to the inbreeding -- mistaking correlation for causation. Whereas we know, due to subsequent improved genetic and medical information, that in famous cases where it was popularly assumed that inbreeding was the source of a congenital defect, it had nothing to do with inbreeding: For example, the historically disastrous hemophilia among the descendants of Queen Victoria of the United Kingdom and her husband/first cousin Albert, Prince Consort. Despite frequent intra-marriage among that couple's descendants, not a single incidence of royal hemophilia is now attributed to inbreeding. Another example is the mental retardation of Prince François, comte de Clermont (and of his sister, Princess Blanche, born 1962), the heir apparent of the current Orléanist pretender to the defunct French throne. Four of Clermont's paternal great-great-grandparents were first-cousins, plus his mother and paternal grandmother also descended from multiple cousin-intramarriages. Nonetheless the retardation turned out to be due to his wife's infection with toxoplasmosis. And of course, nobody wants to mention in this context the brilliant, irresistable and fertile Cleopatra, who descended directly from seven generations of brother-sister marriages. The correct rule-of-thumb here is not "Don't marry your kin", but "garbage in, garbage out -- yet the reverse is just as likely to be true: matings of healthy relatives may produce healthier offspring." Lethiere 21:13, 8 December 2006 (UTC)
While researching inbreeding in humans, I have found reference to the above comment, along with citations of problems with populations that have high homozygosity. It has also been found that some human populations with isolation, and documented genealogies, are relatively free of genetic illness, even though homogeneous. In humans, however, isolation has not generated the races or "breeds", that some researchers such as Sir Arthur Keith, Coons etc. cited in their writings. The current genomic tracings of humans are indicating (relatively) small genetic diversity throughout our species. We have few progenitors,indicated by our mtDNA and the y chromosome, in comparison to many other animals. I am looking for a reference that indicates that our currently known genetic diversity would optimal for a population of 10,000 individuals. I intend to revise the article further on humans. It needs full revision as it is mostly POV. --Kerheals 19:12, 7 January 2007 (UTC)
- Our homozygosity is a function of our youth as a species. When compared with Chimps the most distantly related humans display less genetic diversity than chimpanzee siblings.--Counsel 20:30, 8 January 2007 (UTC)
Youth is a nominative adjective, it is an interpretation of what is found. Technically so are our definitions of what is "human".
In humans, we find such occurences of one male producing millions of descendents through his conquests and raids. This "inbreeding" has produced the y chromosomes AND mtDNA most present in the population. There is NO sign of inbreeding depression in the general population.The radiation of the genetic traits, and its ubiquitous increase of population associated with radiation has caused this. Naill of Noigiallach and Genghis Khan have great expression throughout the population. These warriors and raiders had many "wives" and therefore represent a preponderance across the population. It is NOT so much the youth of humans, but the tendency towards population bottleneck, with subsequent genetic drift of the founding genes have produced this finding. WE reduce our genetic pool by our social conflict. And by the way, so do chimpanzees when they raid other groups adjacent to their home territory.--Kerheals 14:32, 16 January 2007 (UTC)
Mandibular prognathism has not been fully identified as a genetic trait. It is SUSPECTED to be so. The trait has not been identified as either recessive or dominant. It has been found to run in families in Japan as well. [[ http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=16214628&dopt=Abstract]] --Kerheals 04:35, 30 January 2007 (UTC)
[edit] Natural Selection
- It is possible for a population to become inbred without inheriting deleterious traits. For instance the cheetah is a highly inbred species, resulting from a population bottleneck. Many island species are also highly inbred. This is more likely in a population where natural selection is acting. I'm pretty sure natural selection is always happening, it's not something that you can turn off.
I think the answer is Yes, if I understand the question --Michael Johnson 12:34, 4 October 2006 (UTC)
[edit] Domestic Animals
We have what appears to be good information there, however, it should be kept in mind that the goal is description, not advice on how any particular editor believes breeding should be done.--Counsel 20:06, 8 December 2006 (UTC)
[edit] Bad Assumptions
Much of this article is written with the assumption that a breeder is infallible. Take the following paragraph for instance:
- "Natural selection works to remove individuals who acquire the above types of traits from the gene pool, therefore many more, in the first generation of inbreeding, will never live to reproduce. In biology, the fittest are those who survive and breed. Over time, with isolation such as a population bottleneck, caused by purposeful (assortative) breeding or natural environmental stresses, the deleterious inherited traits are culled."
Firstly, it is a poor assumption that "many more" of the first generation will never live to reproduce. Tp what organisms does this refer? Brine shrimp? Sea Turtles? Trees? Dogs? People? It is not possible to generalize over such a broad spectrum. The second sentence states that only the fittest survive in biology. This may be true of collage biology courses, but not of all organisms. In nature the fitter animals are more likely to survive and reproduce, but in fact all might survive in any given generation or all might perish. It depends upon what organism and what environment we are talking about. Lab rats with horrible defects might survive, sea turtles in the wild might not. The next sentence states that "assortive breeding" culls deleterious traits, ipso facto. This assumes that the person controlling the breeding is able to identify the traits, knows how to eliminate them, and chooses to avoid them. If this were true even most of the time such things as hip dysplasia would not exist in dog populations. In fact, they are increasing. The omniscient breeder assumption that pervades this article needs to be culled.--Counsel 23:05, 21 December 2006 (UTC)
The omniscient anti breeding status of the previous article was not based in genetics. The fittest in biology may not be the "best" choice or the most beneficial for the survival of the species, the article now fairly presents what the issues are in inbreeding. In the first generation(not necessarily a single breeding, statistics show that no deleterious phenotypes are also probable) of inbreeding deleterious traits are most often expressed, that is a fact in ALL organisms, it is a basic tenet of Mendelian genetics. The article previously made no distinction between the "fittest" in a biological sense and the "fittest" in the sense of survival in terms of "strength" and vigor. It is a theoretical error to assume that the strongest survive. This is not always the case, specifically with recessive deleterious traits. The previous article made an error in terms of its emphasis on the strength and vigor. The fittest in biology are simply those who survive and breed. Casual or "backyard" breeders have been responsible for the over expression of deleterious traits in both cattle and domestic companion animals. Such breeders are not assortative(and therefore not in the best interest of a breed) at all. Assortative breeding must, by definition, take the various genetics views into account, and must include requisite culling, which can be distasteful when we are discussing humans. If a breeder is not aware of the traits, then assortative breeding is an impossibility.The article now discusses how to identify the traits, identifies culling as the means of removal, and identifies the benefits of removal by culling. Culling may be accomplished by either euthanesia , natural death(selection) either in utero or after birth, or by sterilization of those who express genetic illness. The previous versions were far to close to the animal rights view, which is by nature, anti breeding. In fact there were many errors of fact, and presentation of genetics theory, specifically in the discussion of cheetahs. Finally what purpose is the discussion of royal families? A previous talk participant pointed out the errors in the outcrossing paradigm that was present within the arguments. Why is it that no changes were made on the entry? --Kerheals 17:11, 24 December 2006 (UTC)
[edit] Moved The Rothschilds from the article here for verification.
===The Rothschilds=== Among the descendants of Mayer Amschel Rothschild, the founder of the famous financial and banking family, many of the men married their brothers' daughters or cousins related through the male line, neither of which practices is forbidden by Jewish law. They also had the tradition that only male descendants in the male line could participate in the business, though daughters did inherit considerable wealth. These two traditions were a means of keeping the business closely in the family. This was the reason that, in 1901, the Frankfurt branch of the family business was closed when the male line that managed it died out.
Please provide a source. I know the entire article is unverified, but this is rather controversial, especially "neither of which practices is forbidden by Jewish law".--132.69.234.73 14:50, 19 March 2007 (UTC)
[edit] Charles II of Spain
Tagged "Dubious" for assumption without genetic evidence that his negative traits resulted from inbreeding. See Talk:Inbreeding#POV? for specific discussion. Lethiere 05:09, 26 March 2007 (UTC)
