Monitors may be natural inbreeders…

[Jeff_Favelle]

If you inbreed with your sister you will see traits good and bad compounded

Humans have not had natural selection working on them for millions of years to weed out deliterious recessive alleles. Most reptiles in the natural world have. I don't think you can draw comparisons between us and wild animals. We're due for a catastrophic die off. No question. Too much outbreeding? Doubt it. More like too much medicine (creating super bugs) and too much of the weaker getting to breed. Why do you think there are more cases of all the "syndromes" every year. Every single person is kept alive. There is no survival of the fittest in humans. Its survival of EVERYONE. The human race gets significantly weaker every generation. More in some areas than others. But culturally, its impossible for us to evolve. Our sociology won't allow it.


http://www2.uic.edu/~vuletic/top7.html

http://www.aepryus.com/evolizer/BioPaper.html

[Tim_Cranwill]

Amen! It's so true...

[Steeve B]

Ryan excellent exemple, Thanks!

[mbayless]

Hi Ryan,
Good post. I might say: Medicine has altered the gene-pool significantly for the last 50 or so years now. Since Amniosyntesis, genetic afflictions like 'X-factor', 'Downes', 'pin-heads' etc.... can be diagnosed and aborted before they are born; it is phenotype/genotype modification. Premi-kids are born at 5-months now, where-as when I was born at 6 months 4+ decades ago, they told my mother "He'll be dead in a week, have another kid" - so technology has altered the "Survival of the Fitest" so that fit/non-fit can live and pass on genes too...but eventually, it all works out in the end. You can play with 'Mother Nature', but you cannot 'MESS' with her! She is a tempermental Lady!

MN keeps trying to mess with us: SAARS, now Avian-China flu H-5 which is potentially catostrophic if it spreads like 1918-19 flu pandemic! If it does, it could wipe out a billion people! (somehow that does not sound so bad really....).

cheers,
markb

[crocdoc]

I think there are still a few crucial points being missed here:

1. almost every animal ever studied has shown inbuilt mechanisms to prevent inbreeding. Why jump to the conclusion that monitors are the exception because they get along together when raised together (as do cats and dogs)?
2. No matter how inbred our captive reptiles are, reptiles have been bred in captivity with regularity only in the past 20 or so years. That simply does not compare to the millions of years we are talking about in evolutionary terms.
3. mutation works at way too slow a rate to accomodate rapid adaptation to change. Monitors are a very adaptable group and have radiated quite well: there are a lot of species all close enough to still be considered a single genus - this indicates fairly rapid evolutionary change rather than them being static (as you'd expect if they were genetically identical, which they'd pretty much have to be once they've weeded out all recessive deleterious genes - which would be near impossible, anyway)
4. some crocodilians (smooth fronted caimans, for example) use termite mounds to nest against, for warmth in their rainforest habitat. Crocodilians are more closely related to birds than they are to lizards, so the use of termitaria may or may not be an independantly evolved habit. Either way, it doesn't really add to the story.
5. has anyone actually looked at the DNA of rattlesnake populations to see who is mating with whom? It's likely that snakes from the same den will share certain smells (they'd be from the same locale), but are they chosing close relatives from the same den or the least related individuals? A recent thorough study of cunningham's skinks (which hang out in colonies of related individuals) has shown that they go to great lengths to avoid inbreeding. Had no one checked the DNA of adults, youngsters and neighbouring colonies, casual observation would have lead to the conclusion that they were inbreeding.
6. What would be the evolutionary incentive for monitors to inbreed intentionally, being probably the first ever animal to be proven to do so? If it is to avoid being killed by mates, we are assuming that wild ones kill each other the way captives sometimes do, which is not a likely scenario. A study done on the reproductive biology of lace monitors had a very stable population of breeding adults in the study area. The only animals that died were roadkilled.

So, why would they need to inbreed if it is evolutionarilyy advantageous for them to outbreed? Anyone?

[mbayless]

In a confined space, in captivity, breeding among juveniles, adults, whomever, wherever occurs in higher (and perhaps) lower vertebrates as well! Inbreeding could be a artifact of captivity, and anyone who has taken a biology class or has common sense can see it is not a natural act among higher vertebrates or of Mother Nature's devine scheme of things.

Mankind has made it taboo, and a for good reason. Look at the British Royal Family lineage, and it is full of inbreeding, crossbreeding, and they have Monarchs with mental illness (Nicholas I, Russia; King Gustav V, Sweden), bleeders (H.R.H. Prince Alexey Romanov, Russia; H.R.H. Leopold II, Belgium), and a plethora of other maladies spread throughout Europe due to their inbreeding practices....

Cheers,
markb

[crocdoc]

... but aside from the reasons inbreeding is usually considered 'bad' from an evolutionary point of view (that's usually a given), I'd like to know what advantages an animal could gain by going 180 degrees in the other direction: ie intentionally inbreeding. Rather than discuss the 'whether' (whether they do or don't - which could be tested by someone with a grant), perhaps I'd have a better understanding of the other side of the discussion if I knew the 'why'.

[mudflats]

First off this is probably one of the most informational posts, glad this was all discussed.
One issue i have seen was one of my favorite herping spots, a single ditch only brought to have water by the rain, and was miles away from any other water bed etc... They where around 15-20 florida water snakes in this ditch. That alone is a prime example of how inbreeding does not affect snakes.

[Scales Zoo]

I'll have to try to find the other thing I read about rattlensnakes, but this is about that study.

http://news.nationalgeographic.com/n...tlesnakes.html

DK, I don't think anyone has done DNA studies yet - and I shouldn't speculate about inbreeding because of family bonds. The above article did mention female snakes showing "family bonding" more than males.

Would be interesting to study, to see if the snakes are inbreeding, or if males go find females in dens miles away. Rattlesnakes, alone - are like monitors. They are so unique, but so little is really known about them.

There was another study on rattlesnakes about the rattling of tails causing static voltage, and possibly turning the snake into an electro magnet. The studiers assumed it may help them to find water, or food. I have to wonder if this might not help them travel 20 miles from a hole, and come to the same one in the fall. Heat pits, a rattle, venom, the ability to articulate each fang independantly like a finger...... one of the coolest reptiles out there for sure.

Ryan

[crocdoc]

Originally posted by mudflats
First off this is probably one of the most informational posts, glad this was all discussed.
One issue i have seen was one of my favorite herping spots, a single ditch only brought to have water by the rain, and was miles away from any other water bed etc... They where around 15-20 florida water snakes in this ditch. That alone is a prime example of how inbreeding does not affect snakes.

Unfortunately, mudflats, finding a group together like that does not necessarily indicate inbreeding until someone finds out how much mixing there is with other populations. Someone I know put a transmitter on a diamond python living in the suburbs of Sydney - it inhabited a treed reserve between suburban streets and was assumed to be isolated. In the breeding season, it attracted seven males, which clearly came from far and wide. Things are not always as they seem from casual observation.

Even if your small cluster of water snakes were inbreeding, we'd still only be talking about a limited number of generations rather than thousands

[crocdoc]

Ryan, thanks for the link to the article. Unless I read it incorrectly, it isn't suggesting that they inbreed, but suggesting that they hang out together with related individuals (in the study, it was related females that were hanging out together, not males and females). This would make them like the cunningham's skinks I mentioned above, which hang out in family groups. Now someone needs to test the DNA of the offspring to check against that of the parents to see if related rattlesnakes are inbreeding, or if they have mechanisms to prevent this, as do the skinks.

[Steeve B]

Dk I really like your insight, its always mind-bending for me. I wish I hade answers to all your questions, but I don’t, all I can offer is my own vision based on my understanding. Herpetoculture is the science of reptiles husbandry, in this we are following the foot steps of great man’s, many you know the work better then me, you once expressed in one of our exchange you embraced Darwin’s theory on evolution of species, Then you must know that his work on the Galapagos lives on today, His very own foundation punched not once but twice into his own theory by the discovery of inbred finches developing larger more adapted beaks and the cross breeding of land and marine iguanas. This says a lot, reptiles do what they need to survive, inbreeding out breeding crossbreeding are all survival tools.

Mark;
I have much respect for you and love you as a brother, pleas stop embarrassing me and stick to the subject.
Ps. Pinhead is a syndrome of rapid growth, its got nothing to do with pre-birth

[crocdoc]

Actually, the finches are an excellent example of why animals need genetic diversity to adapt. A population of finches reached the islands, where there were still many niches left unfilled. The finches radiated and formed a whole species group filling the niches.

It is possible this was accelerated because they were isolated, inbreeding and therefore recessive genes were expressed which included bill shapes and size ts. The important factors, though, are that:

1. the inbreeding was forced through isolation
2. the birds landing on the island weren't all genetically identical from thousands of generations of inbreeding and therefore had the genetic diversity amongst them to produce the many finch species we see there today.

As far as the iguanas go, that's typical island stuff: a population gets isolated on an island and quickly becomes a new species through boatload or founder effect. Again, this is forced inbreeding, not an inherited behaviour.

[mbayless]

Steve: You do not say the truth, as your past actions do not agree with your words here.

Pinhead: It is a genetic - female recessive trait malady where the family members exhibit microcephaly. It often is common in families, much like the 'Lobster-hands' malady. My Mother studied such people in Denmark 1947-1949, some of whom had been in the English-banned film "Freaks" (1935). They were terribly ******** and often die young. Macrocephalic persons are also short-lived ******** due to opposite conditions.

Inbreeding has been seen in scenarios of isolation, confinement and related conditions, as seen in captive reptiles, mammals, etc....so is it natural? Or a natural reaction to an artificial/harsh/stressed conditions?

I do not know of your report on Galapagos inbreeding finches, unless you are speaking of "The Beak of the Finch" By John Weiner. Ecophysiology and microhabitat and food availability were factors determined there on how/why the Darwin Finches' were evolving in a 20 year cycle...it is a fascinating book.

markb

[Jeff_Favelle]

I'd like to know what advantages an animal could gain by going 180 degrees in the other direction: ie intentionally inbreeding. Rather than discuss the 'whether' (whether they do or don't - which could be tested by someone with a grant), perhaps I'd have a better understanding of the other side of the discussion if I knew the 'why'.

If the local environment is in a state of stasis (unchanging) and the local fauna have evolved for thousands (millions) of years to exploit their respective niches to the fullest, being reflected in their genomes (obviously), then how is introducing genetic diversity going to help them? Obviously it would help them against unwanted change (adaptation purposes) and possibly against disease ("possibly"), but that's only if the environment changed. And that's only if disease was introduced. Nature ain't quick. Disease just doesn't "happen" (rare), unless some funny bi-ped animal (us) causes it directly or indirectly. Adding new genes that aren't capable of exploiting the local niches (microhabitats) better than the next set of creatures isn't condusive to keeping the stasis. It will create unbalance.

And this is the very core as to why is a BIOLOGICAL NO-NO to release animals even 1 or 2 km from where they are collected. Ever wonder why all the books on reptile collecting suggest to release the animal(s) PRECISELY where they were found?

Nature is complicated. Saying that inbreeding is ALWAYS bad and serves no purpose because its based on HUMAN cultural influences is just as bad as saying that everything should be inbred and that genetic diversity is evil. Every case is specific and we cannot begin to understand the complexity to make those decisions with what we currently understand. That's why we try to preserve what we have in the here-and-now. If genetic diversity was so great across the board, then why aren't all the scientists catching animals from different metapopulations and releasing them into others. More gene flow, more diversity, it would great!!

Nope.