what are the most likely genetic mishaps to occur when sibs have a child together?
can sibs have a healthy baby? will that baby later have healthy babies? (not necessarily with a sib)
are there any advantages (genetic or otherwise)?
Same as for any other pairing, AFAIK. Good genes get better, bad genes get worse.
I understand there was many generations of sibling pairing in the Egyptian royal family (of which Cleopatra was one) and they were OK.
Some researchers have reported a mysterious inclination (among the children of sibling pairings) to live in Tasmania.
joffrey baratheon
what could possibly go wrong.
Rule 303 said:
Same as for any other pairing, AFAIK. Good genes get better, bad genes get worse.I understand there was many generations of sibling pairing in the Egyptian royal family (of which Cleopatra was one) and they were OK.
OTOH there was the Habsburg jaw. Which was ok for the blokes, they could hide it under beards, not so good for the girls. And two toed Africans.
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
My apologies, the mythology might have got to my memory. Cleopatra could not really be said to be from a royal family.
Wiki gives:
Wiki said:
The high degree of inbreeding amongst the Ptolemies is also evident when one considers Cleopatra’s immediate family. Her father was likely the uncle of Cleopatra’s mother. There were three uncle/niece and three brother/sister relationships in her ancestry going back to a single set of either great grandparents or great great grandparents, depending on how the ancestry is traced.
Peak Warming Man said:
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
Oh yeah. Hunter gatherers are right up with the latest research on biological diversity. It’s not because the other tribe has more hotties….
;-)
Peak Warming Man said:
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
Plus da ones over de hill be better lookin’.
Rule 303 said:
Peak Warming Man said:
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
Oh yeah. Hunter gatherers are right up with the latest research on biological diversity. It’s not because the other tribe has more hotties….
;-)
Yes they had NFI why they were doing it, that’s why I cunningle slipped in the word ‘latent’
I’m an intellectual now.
Peak Warming Man said:
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
Does this still happen in the suburbs of Brisbane?
Peak Warming Man said:
Yes they had NFI why they were doing it, that’s why I cunningle slipped in the word ‘latent’
I’m an intellectual now.
They weren’t completely ignorant to the benefits of genetic diversity. Many primitive groups had elaborate rules designed to limit in-breeding.
neomyrtus_ said:
I wish.
Peak Warming Man said:
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
Does this still happen in the suburbs of Brisbane?
Peak Warming Man said:
Yes they had NFI why they were doing it, that’s why I cunningle slipped in the word ‘latent’. I’m an intellectual now.
Hmmm… There’s a variety of attempts to explain selection from outside one’s group. Some of them look at factors like political alignment, increased access to power/status/wealth etc, which I find more convincing than ideas about genetic diversity.
Witty Rejoinder said:
Many primitive groups had elaborate rules designed to limit in-breeding.
Did they?
Is this thread about human, mammal, plant or insect incest?
A lot of plants can self-fertilise if needs be.
Rule 303 said:
Witty Rejoinder said:Many primitive groups had elaborate rules designed to limit in-breeding.
Did they?
I may be overstating my case but I think the near universal aversion to incest points to some primitive understanding of the dangers of inbreeding.
neomyrtus_ said:
Is this thread about human, mammal, plant or insect incest?A lot of plants can self-fertilise if needs be.
I assumed human, I was going to post about my inbreeding aquatic captives, but didn’t think Arts would be overly interested in that.
Rule 303 said:
Peak Warming Man said:Yes they had NFI why they were doing it, that’s why I cunningle slipped in the word ‘latent’. I’m an intellectual now.Hmmm… There’s a variety of attempts to explain selection from outside one’s group. Some of them look at factors like political alignment, increased access to power/status/wealth etc, which I find more convincing than ideas about genetic diversity.
Yes, marrying (or hostaging) your daughter to the tribe over the hill has always been used by chiefs or royalty to increase the chance for peace or even act as a foreign envoy.
In some African tribes the raids to get de wimmins were all about stopping that tribe from breeding. Easier to raid de wimmins when they are away from the hunting fellows than taking on the warriors.
Tis a rich tapestry.
I think one of the first things they’d (the siblings) would have to get around would be the Westermarck Effect, though that’s more about them being together in a relationship than the question asked. I recall reading about a German couple who were brother and sister who’d been separated at birth and never met until they were adults. They fell in love and had several children before they decided to get married. The were required to have blood tests, and that’s when they discovered they were siblings. Because of the way German law is written, the brother was convicted of incest and imprisoned. The point of all this, of course, wsa the children. As far as was known, they were fine.
I’ll try to find some details.
Here we go: Their names are Patrick and Susan Stübing. He’s 8 years older than her, and they’ve got four children.
http://en.wikipedia.org/wiki/Patrick_St%C3%BCbing
http://www.spiegel.de/international/germany/dangerous-love-german-high-court-takes-a-look-at-incest-a-540831.html
http://www.theguardian.com/world/2007/feb/27/germany.kateconnolly
These stories are more about them than their children, though.
Michael V said:
neomyrtus_ said:I wish.
Peak Warming Man said:
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
Does this still happen in the suburbs of Brisbane?
Not necessarily stealing. Aboriginals had complex social rules for meeting other tribes on neutral ground for gene swapping.
neomyrtus_ said:
Peak Warming Man said:
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
Does this still happen in the suburbs of Brisbane?
No self respecting southerner would ever steal a chick from north of the river.
Could ask the Fritzl family, seemed fairly fecund.
Dropbear said:
neomyrtus_ said:
Peak Warming Man said:
Stealing girls from other tribes was something common to all native tribes around the world, probably driven by a latent quest for tribal genetic diversity, a healthier stronger tribe.
Does this still happen in the suburbs of Brisbane?
No self respecting southerner would ever steal a chick from north of the river.
Oi!
Arts said:
what are the most likely genetic mishaps to occur when sibs have a child together?
depends on the genotypes of the siblings
can sibs have a healthy baby? will that baby later have healthy babies? (not necessarily with a sib)
Yes. Yes.
are there any advantages (genetic or otherwise)?
Persistence of a sets of advantageous alleles (see ring bivalents and obligate selfing / inbreeding systems)
Ability of alloployploids to breed.
Witty Rejoinder said:
I may be overstating my case but I think the near universal aversion to incest points to some primitive understanding of the dangers of inbreeding.
Yeah OK.
On the numbers alone, one doesn’t need to go back many generations before the number of people required (to sustain any meaningful diversity) become many times greater than the human population of the earth.
There’s also been attempts to explain it with chemistry – Particularly Pheromones – That might also have some validity.
This might help a bit:
http://www.aboriginalculture.com.au/socialorganisation.shtml
In horse breeding (and other mammals) the language is about in-breeding, line-breeding and out-breeding (or out-crossing).
Out-breeding is what is sounds like… no relation… and hence very low chance of deleterious genes being duplicated.
Line-breeding is about breeding with the relatives of one or more horses with desirable characteristics. We have had good results using this system.
In-breeding is crossing siblings together or parent to offspring or offspring to parent in the hope of reproducing another outstanding specimen while risking the expression of some deleterious gene. This was successfully used by a well known breeder in the Arabian world who had a world beating stallion. He put the male offspring over his own mother and put sibling to sibling.. AFAIK there were no adverse outcomes.
If you built non-biological machines that replicated through something analogous to sexual reproduction (god knows what that might be) what would you build into the machine that’d work like an incest aversion mechanism (expressed also as taboo).
Something more than leaving two late eighties VHS video machines of the same model from the same production batch in the cupboard together, you know those models that truly ‘only just work’, and they copulate and had baby video machines.
On a more serious note, with humans, in which the dice throws of DNA recombination and unfolding in the womb onward to bringing the offspring to breeding age are subject to composite nature nurture and nurture nature, these dice throws are important to diversity of trait potentials. What though has selection happened upon as a mechanism to disincline sex and breeding between those ‘too’ closely related. Is it more built into aspects of the social instincts hinging around fear of disapproval and isolation (reduced access to resources). Granted though the flipside of the social may be seen as private doings. I mean sex is mostly performed in private (which need not just mean two people, it can include orgies).
Instincts like ‘revulsion’ seem powerful but somewhat given to being given specificity by experience, social environment, culture (tha law), conditioning perhaps. Amplified by social or private or individual experience, reinforcers it could be said (formal, but likely mostly informal). Acceptance too, though not mostly perhaps an adverse experience – that attractive – may be a path paved with revulsion way away at a safe distance (hinting revulsion may have an interesting and perhaps comforting flipside people mentally occupy).
I’d like to know if there are any human beings that most of us would consider within the range of ‘normal’, that have no active revulsion mechanism. That is in fact not active in some way most of the time.
Do right thinking normals that keep well within the boundaries of ‘safe company’ and the ‘moral community’ have a more or less active revulsion mechanism (or cluster of mechanisms that might be roughly defined this way, here for my purposes) than say a ‘deviant’. Does being well behaved require some intimate insight into deviancy.
I think every recombination effort is a nurture nature nature nurture test. Going wider broadens the test range, so to speak, broadens the overall resource base, which both has risks and positive potentials, but more serves individuals and groups extending to longer timescales. It’s more adaptive, lends more to adaptation.
Probably equally important to the cognitive tools evolving would be the improvements in immune function. That a teeneger back through history made it to breeding age without being killed or disabled terribly by disease, was probably an important test.
Going broader with DNA recombination probably assists the better DNA go around the less adaptive DNA expressions. Like if your whole family was whiped out by spanish flu and you managed offspring with someone very unrelated, your DNA was in with a chance. And even if that effort failed your sisters and brothers did the same, again likely with someone ideally very unrelated, so the DNA (differences and similarities) were in with a good chance around the place, going broad.
Life is dice.
Wocky said:
I think one of the first things they’d (the siblings) would have to get around would be the Westermarck Effect
The Westermarck effect, or reverse sexual imprinting, is a hypothetical psychological effect through which people who live in close domestic proximity during the first few years of their lives become desensitized to later sexual attraction. This phenomenon, one explanation for the incest taboo, was first hypothesized by Finnish anthropologist Edvard Westermarck in his book The History of Human Marriage (1891). Observations interpreted as evidence for the Westermarck effect have since been made in many places and cultures, including in the Israeli kibbutz system, and the Chinese Shim-pua marriage customs, as well as in biological-related families.In the case of the Israeli kibbutzim (collective farms), children were reared somewhat communally in peer groups, based on age, not biological relation. A study of the marriage patterns of these children later in life revealed that out of the nearly 3,000 marriages that occurred across the kibbutz system, only fourteen were between children from the same peer group. Of those fourteen, none had been reared together during the first six years of life. This result suggests that the Westermarck effect operates during the period from birth to the age of six.
When proximity during this critical period does not occur — for example, where a brother and sister are brought up separately, never meeting one another — they may find one another highly sexually attractive when they meet as adults, according to the hypothesis of genetic sexual attraction. This supports the theory that the populations exhibiting the Westermarck effect became predominant because of the deleterious effects of inbreeding on those that didn’t.
Contrasting Westermarck and Freud
Freud argued that as children, members of the same family naturally lust for one another (See Oedipus complex), making it necessary for societies to create incest taboos, but Westermarck argued the reverse, that the taboos themselves arise naturally as products of innate attitudes.
Steven Pinker wrote on the subject:
The idea that boys want to sleep with their mothers strikes most men as the silliest thing they have ever heard. Obviously, it did not seem so to Freud, who wrote that as a boy he once had an erotic reaction to watching his mother dressing. But Freud had a wet-nurse, and may not have experienced the early intimacy that would have tipped off his perceptual system that Mrs. Freud was his mother. The Westermarck theory has out-Freuded Freud. —Steven Pinker, How the Mind WorksCriticisms
Sociologists and anthropologists have criticized the validity of research presented in support of the Westermarck effect and the contention that it serves as an ultimate demonstration for the viability of natural selection theory in explaining human behaviour. For example, a 2009 study by Eran Shor and Dalit Simchai demonstrated that although most peers who grew up closely together in the Israeli kibbutzim did not marry one another, they did report substantial attraction to co-reared peers. The authors conclude that the case of the kibbutzim actually provides little support for the Westermarck Effect and that childhood proximity cannot in itself produce sexual avoidance without the existence of social pressures and norms.
AFAIK, I’ve never met a human whose parents were siblings, but I used to know a woman whose parents were first cousins. They grew up on different continents. When they first met, as young adults, they instantly developed a strong attraction for each other.
transition said:
If you built non-biological machines that replicated through something analogous to sexual reproduction (god knows what that might be) what would you build into the machine that’d work like an incest aversion mechanism (expressed also as taboo).
True, incest does reduce genetic diversity, and over the long term such loss of diversity combined with accumulation of unfavourable mutations can make it risky for close relatives to breed. So incest is mainly a problem for species that have already been through a major genetic bottleneck. Humans are in this category…
in the future humans will be bred by machines as a hobby
wookiemeister said:
in the future humans will be bred by machines as a hobby
Yep. The day we invent machines so human-like they need a hobby; we’re fucked.
party_pants said:
wookiemeister said:
in the future humans will be bred by machines as a hobby
Yep. The day we invent machines so human-like they need a hobby; we’re fucked.
Arts said:
what are the most likely genetic mishaps to occur when sibs have a child together? can sibs have a healthy baby? will that baby later have healthy babies? (not necessarily with a sib) are there any advantages (genetic or otherwise)?
> what are the most likely genetic mishaps to occur when sibs have a child together?
Good question. The answer would be that it could be anything, but most likely to be the most common recessive mutations. This would vary a lot depending on where in the world. Three damaging recessive mutations are Cystic Fibrosis, Sickle Cell Anemia and Tay Sachs Disease. I’ve heard it said that the average person has three dangerous recessive mutations, a sibling would have half of these, so there’s more than a 50% chance that the child would have a dangerous disease.
> can sibs have a healthy baby? will that baby later have healthy babies? (not necessarily with a sib) are there any advantages (genetic or otherwise)?
Yes, yes and yes. In fact, a healthy baby from siblings would have fewer dangerous recessive genetic mutations than normal. Places where marriages of close relatives are permitted, I’m thinking of parts of India, have children that are as healthy as normal. In stock breeding, the breeding of close relatives is common – where it works they call it “line breeding”, where it fails they call it “interbreeding”. Line breeding is commonly used with dogs, cattle, rabbits and birds.
>>In fact, a healthy baby from siblings would have fewer dangerous recessive genetic mutations than normalIn fact, a healthy baby from siblings would have fewer dangerous recessive genetic mutations than normal
I don’t follow that reasoning.. some sort of temporal reversal involved.
>>In stock breeding, the breeding of close relatives is common – where it works they call it “line breeding”, where it fails they call it “interbreeding”. Line breeding is commonly used with dogs, cattle, rabbits and birds.
That statement is complete rot. I explained line breeding previously.