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I was reading the busy post down below about intergrading/crossing Eastern and Florida kings in the wild and in captivity and the resulting dissention it brings up.

Just wanted to add a few comments, and didn't feel like finding the appropriate place in the tiers of posts below. So pardon the exhumation of this topic.....

I think it is easy for us to overlook the fact that there is no such thing as a "pure" eastern kingsnake. People have a tendency to think of the "classic" narrow-banded, high band count NJ snakes as "classic kings" and that the wide banded, yellowish ones, are the result of "contamination" of the gene pool by Florida Kings. But this principle is based back on the old typological species concept, where any individual can be close to the "perfect" form for a species or subspecies.

With our current understanding of populations and gene flow, this type of philosophy has been shown to be biologically unsound. There is no "pure" form of any subspecies or morph. And furthermore, there isn't a contiguous population of eastern king from NJ down to northern Florida. There are hundreds of little populations, each of which is isolated to varying degrees from other populations.

Each of these small populations is under evolutionary pressures that result in changes in gene frequencies within that population. Those changes can result in populations developing speckling, wide bands, narrow bands, more bands, purple bands, whatever. And there doesn't have to be a Darwinian "survival of the fittest" type explanation for the changes. Simple random changes in gene frequency (genetic drift) occur in all populations in isolation.

For example, many of the eastern Kings I have seen from around the Virginia Beach area have very wide white bands. They are wider than other VA kings and wider (and whiter) than those of coastal NC kingsnakes, generally. Is this a reflection of "impurity" in this population? Of course not, it is the result of an increased frequency of the wide white genes in this population through its isolation from surrounding populations.

Furthermore, the isolation of the populations could be due to development (all the suitable habitat has been destroyed around a city park), movement of river flow, changes in sea level, etc. These sorts of changes take place all the time and over long periods of time. Therefore, a population of Eastern Kings that currently appears contiguous (say in two neighboring counties) might have been isolated from each other a few hundred years ago by a river or might be isolated next year by building a new resevoir.

But this perceived population structure is little more than a snapshot in time. Boundaries and barriers constantly change. Therefore, similarities between kingsnakes northern FL and the Outer Banks could be the result of gene flow between these areas in the past, but it is more likely to be the result of genetic drift in an isolated area on the coast of NC.

In fact, you could argue that the speckling seen in OBKings, Edisto Island Kings, Mosaic Kings, some FL populations, etc., suggests not that there is any sort of gene flow, but that somehow, these kingsnakes in isolation have a tendency, through genetic drift, to develop speckling along their sides. Maybe it is reversion to a "primitive" color pattern (an idea suggested indirectly by Blaney in 1977).

Eastern Kings from northern Florida are as much "pure" eastern kings as those from New Jersey. Why? Because the field guide says they are. And since the concept of an "Eastern Kingsnake" is almost completely illogical from a population biology sense, that seems as good a reason as any to draw the lines where they do. And if you don't like the lines where they fall today, you can redraw them so that any kingsnake between Miami and the Maryland state line is an intergrade. That's fine, but it doesn't change anything real.

Goini (I won't use that "other" name!) evolved in isolation. Now they are being genetically swamped by eastern kings from other areas of the panhandle. Eventually, this morph will probably disappear, and no amount of conservation or protection can save it. It is being eliminated by eastern kingsnake genes. The only thing that could "save" it would be new isolation (change in sea level, etc). If that happens, FL panhandle residents have more to worry about than eastern kings!
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Chris Harrison

Chris,
So what you are saying is, in these isolated population of snakes "line breeding" is occuring in the wild?
I am a firm believer that anomalies will occur when line breeding takes place and I agree with you 100%. We, as breeders select favorable "looking" specimens and breed them together. After generations of doing this a "different" looking specimen will occur. These such pairing have a slim chance happening in the wild but we help them by our selective propagations.
I think that breeding a pair of Goini that were collected a few yards apart for many generations will produce something with a different appearance than the founding specimens. During line breeding all the "favorable" traits are gathered together producing outstanding specimens, but other "unfavorable" traits will also be gathtered throughout generations and produce a not so outstanding specimen.
I do think this has a chance of happening in the wild, but in very isolated populations where other influences are absent. It is hard to think that their are such isolated populations any more, though. Influencial traits are inevitable.
Thanks Chris for the post.
John Lassiter

So what you are saying is, in these isolated population of snakes "line breeding" is occuring in the wild?

If by "line breeding" you are referring to inbreeding (mating of individuals who are in some way related), then no. These isolated populations are large compared to herpetocultural standards.
A really small isolated population might consist hundreds of adults and since there is relatively random mating in the wild, the amount of inbreeding should be minimal. However, the frequencies of alleles that are rare elsewhere could, by chance, increase.

For example, imagine a bad flood year or two. Suppose the bulk of the population lives along a river bottom and a few individuals live in the less optimum upland habitat. During a huge flood year, many adults and all the eggs in the river bottom are wiped out. The eggs that hatch on the uplands will lead to recolonization of the river bottom. If that clutch of upland babies came from a particularly wide-banded female, the frequency of wide-banded snakes in the river bottom in the subsequent generations will be higher.

I am a firm believer that anomalies will occur when line breeding takes place and I agree with you 100%. We, as breeders select favorable "looking" specimens and breed them together. After generations of doing this a "different" looking specimen will occur.

These anomalous individuals no doubt occur in the wild, but they are more common in captivity due to the inevitable inbreeding.

I think that breeding a pair of Goini that were collected a few yards apart for many generations will produce something with a different appearance than the founding specimens.

This is seen already. Striped and unicolored goini are much more common in captivity than they are in the wild. In fact, when I was interested in goini (mid 80s) there were no striped/unicolored snakes available (in fact, I didn't know they existed - goini were "blotched kingsnakes" - which are still the best looking ones IMHO).

During line breeding all the "favorable" traits are gathered together producing outstanding specimens, but other unfavorable" traits will also be gathtered throughout generations and produce a not so outstanding specimen.

Inbreeding doesn't select for good traits or bad, it just increases the frequency of homozygotes. If the homozygous condition is something "good", we say that we have improved the line through selective breeding. If the homozygous condition is something bad, we call it a result of inbreeding. Either way, it is the same cause/result.
Chris
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Chris Harrison

If by "line breeding" you are referring to inbreeding (mating of individuals who are in some way related), then no. These isolated populations are large compared to herpetocultural standards.
A really small isolated population might consist hundreds of adults and since there is relatively random mating in the wild, the amount of inbreeding should be minimal. However, the frequencies of alleles that are rare elsewhere could, by chance, increase.

>> Chris, thanks again for the great post and information. I think that since breeding in the wild is relatively random, inbreeding is not only minimal, but a high occurance. If snakes are confined to a specific population then inbreeding will be high. I also believe that snakes from other species will travel into these populations on rare occurances and share their genes so to say. This genetic material can be moved across many counties and even states this way. So yes, "pure" populations are rare. This is my honest opinion and thank you Chris.
John Lassiter

This I realize is a very simplistic statement but evolution wouldn't work without some level of inbreeding.

Excellent post Chris ! I think this should be posted every few months for a reminder. Again excellent points !

Keith
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What we choose to call them does not change what they are. I especially agree with your ideas that these snakes in reality have become a series of isolates. It would make sense that selective pressure would play a huge role in the resulting physical characteristics of each. Labeling something as pure is a covenient term for us to place things in some sort of order. Where this purity begins or where it end, or if it exists at all is the question. The subspecies concept is becoming less fashionable every day by the DNA analysts. Much of their work is done in a laboratory by fielding genetic markers. To some degree I think this is good and does provide some insights into relationships on the molecular level. On the other hand if the basis of classification is to place organisms into a meaningful biological order I believe what can be learned in a laboratory is only part of a much larger puzzle. To me the subtle differences that occur in various parts of a species range is interesting and worth noting. When an intergradient population occurs this is worthy of note also and should be viewed as part of the evolutionary process. The fact that various subspecies often have slightly different preferences in habitat utilization, coloration, prey preferences, scalation, clutch size and other aspects makes this all the more interesting. As both a hobbyist and an avid field herper I like holding on to the biological species concept. Anyhow, I'm digressing a bit, but great post and topic. - Phil

Hear, hear and also well said! I couldn't have expressed it better myself! Great post!
Todd

This is how I see it:
The OBK example(which explains why the DNA is identical to Easterns): If on a tiny Island In NC. 10 baby Kingsnakes are born. 8 of them are normal looking, 2 of them have a lot of speckling. As is usually the routine: Only about two of them survive to breeding age. BUT! It happens to be the two that are speckled (just by chance of course). Now (since we're talking about a small Island), these two Individuals go out and spread their genes into the rest of the tiny population. This makes a huge impact on what the future Kingsnakes might look like!
What are the odds of this exact scenario happening? Probably very slim, but when you add all of the tiny populations together hundreds at least, and this (the 10-20 percent survival ratio thing) happens to them all the time, then yes sometimes by pure chance a certain color/trait can become dominant. It could also be that the 'speckled' variety in NC. looked so different to local predators, that they hesitated on preying on these snakes (if only one time), that in turn increased their chances of initial escape/survival into adulthood. - Hence the term "NATURAL SELECTION"!

THE WORLD IS EVER CHANGING - EVOLUTION! -

Zee

It could also be that the 'speckled' variety in NC. looked so different to local predators, that they hesitated on preying on these snakes (if only one time), that in turn increased their chances of initial escape/survival into adulthood. - Hence the term "NATURAL SELECTION"!

Zee,

It could be that speckled snakes have higher survivorship on barrier islands where they are forced to forage in the open. Speckled kings (holbrooki) survive quite well in grasslands and can be REALLY hard to see sitting in the grass! So, maybe selection has had a factor.

However, I think it equally likely that these island populations look different due to isolation of the population and the resultant inbreeding/drift.

Part of the issue here could be the genetic plasticity of easterns. Not every possible pattern is possible due to the genetics of how eastern patterns are formed (there isn't going to be a purple banded eastern, for example). It may be that the eastern genome carries the potential for speckling (again, maybe as an ancestral trait) and that in isolation, the frequency of this allele increases.

No way to know the real answer.
Chris
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Chris Harrison

It needs to be kept in mind that not all OBK kings look like the "classic" captive-bred examples we identify with. I have found several (a good percentage of OBX kings I've found) that look for all intensive purposes like ordinary eastern kings.

Posted by: chrish at Sun Feb 6 16:59:42 2005 [ Report Abuse ] [ Email Message ]

These words, hybrid and intergrade, are terms that have a specific meaning in the field of evolutionary biology. However, outside the field, they are often used more broadly, and in fact, synonymously.

In biological terms, a hybrid is a natural cross between two different species. An intergrade is a naturally occurring cross between two different subspecies or races.

Now, once you take these snakes out of the wild and put them in plastic boxes, the terms lose their meaning as they aren't "naturally occurring" crosses. So it really doesn't matter.

This kind of non-scientific expansion of terminology is common in the herp trade (for example, my snakes are currently brumating for the simple reason that snakes do not hibernate). This sort of (mis)use of scientific terminology is common in "lay" science.

The fact is, as long as we know what we are talking about, who cares if you call it a hybrid or an intergrade. It technically isn't either since it happened in a Rubbermaid container.

This sort of "expansion" of the meaning of a term does no harm. The only harm is done when someone tries to impose on meaning of the word on the other group.

For example, when someone criticizes the Theory of Evolution because "it's only a theory", they are simply demonstrating their ignorance about the two uses of the word theory. The reason....the word theory has a very different meaning in science than it does to the non-scientist. The Theory of Evolution is only a theory in the same way that the Theory of Gravity is, yet I'm not worried about floating out of bed tonight!

There is no problem with there being two (or more) implications about the meaning of a word (hybrid, intergrade, hibernate, theory, etc.) as long as you understand what it does and doesn't imply in that context and don't try to extrapolate one meaning into the other context.
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Chris Harrison

Chris posted this below and it was very well thought out and so much better than I can every do I thought I would copy it up here so those that might have missed it below could read it and gain what they may.

Again Chris great post on this one and the new topic Thank You Very Much for the effort.
Thanks Jason

great post,,,,,,,
this kinda stings me a bit though:

>>Goini (I won't use that "other" name!) evolved in isolation. Now they are being genetically swamped by eastern kings from other areas of the panhandle. Eventually, this morph will probably disappear, and no amount of conservation or protection can save it. It is being eliminated by eastern kingsnake genes. The only thing that could "save" it would be new isolation (change in sea level, etc). If that happens, FL panhandle residents have more to worry about than eastern kings!
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evolved in isolation from what?flaXeastern??, now to say they are being eliminated by e.king genes?, seems kinda odd that there is such a genetic differance in a natural morph that they could be "eliminated",esp. one that is as ever changing as ,blothched,apalachicola,goini,meansi, whatever ya wanna call it is,and there is still a relitively large nat.range so? i dont see the morph dissappearing so much as i see the classification or acknowledgement in the herp comunity that it is just a morph and not a ssp., i remember when they(whoever they are)de-classified l.g.yumensis as a morph and not its own ssp. kinda made me sad but i still refer to them as yumensis anyway i see a similiar scenario w/goini, there seems to be a fascination for some to have morph phenotypes labeled as individual subspecies and pure noless pretty laughable really,but then so is life,,,,,,,thomas

LOL As always a very good post.