at Wed Dec 10 13:09:56 2008 [ Report Abuse ] [ Email Message ] [ Show All Posts by RichardFHoyer ]
Just to add a bit more to our 'brainstorming'.session.
The sample of vouchers I examined from the Santa Cruz Mts. indicates that population belongs to the large morph. So due to geographical proximity, up to now I too considered it likely that the boa population in Monterey County (and San Luis Obispo Co.) would belong to the large form as well. Yet I always try to remain open to alternative explanations.
When I went through my folders on the vouchers I had examined from the Smithsonian, CAS, and MVZ collections, I found just the three Monterey Co. females all of which were somewhat small. Not much can be gleaned from such a small sample so here we have another region that needs to be explored.
Seems to me that at one time, the mountainous areas of Santa Cruz and Monterey Counties were separate by intrusion of the sea into the central valley. So I wonder if that barrier may have any implication on the nature of those two populations.
And like yourself, I originally 'assumed' that the dwarf morph was ancestral. After confirming that the San Bernardino boa population was indeed a dwarf form of the species, in about 1996, I gave considerable thought to the issue large and dwarf morphs. I devised a hypothesis to explain the likely selection factors whereby the large morph evolved from the dwarf form. At the time, I passed those thoughts on to Glenn Stewart and Dr. Robert Mason here at Oregon State U. but haven't concerned myself with that aspect since.
But unless the raw mtDNA data somehow can ascertain the relative ages of populations, then I have to concede that perhaps my original views were in error and there exists the possibility that the dwarf morph evolved from the large morph.
I know so little about mtDNA research but I can envision one potential piece of evidence that may indicate the relative age of populations. You can give me your thoughts about the following: If a large number of mtDNA haplotypes exist in a relatively small geographical region, wouldn't that indicate that over time, a large number of mutational events had occurred? In contrast, if there are much fewer mtDNA haplotypes in a geographical region, would that possibly indicate a much younger age?
Should there be a large number of different mtDNA haplotypes and few identical haplotypes in the San Bernardino and San Jacinto Mts. in relation to other regions, then perhaps relative age can be inferred. Perhaps the ratio of unique to identical haplotypes per given region is such a clue. The existence of 32 identical haplotypes from N. Calif. to B.C. to Montana, Utah and Nevada may suggest such a scenario.
If the frequency of different and identical haplotypes per geographical area can be interpreted as an indication of age, then here again is another argument for testing much larger samples per any geographical area.
As a side note, as I was looking up the information on the specimens I have examined from Monterey County, I ran across three more old vouchers that originated within the Mt. Lassen area. One specimen from the Smithsonian was collected along Mill Creek in northeastern Tehama County due south of Lassen Peak. Then the CAS collection has two specimens collected in 1926 and 1949 with the former coming from the Lake Almanor peninsula and the other from near Westwood. This latter specimens is just about half way between the Northwestern subclade Eagle Lake specimen and Sierra Nevada subclade Quincy specimen in Javier's study.
It would be my guess that Javier and others entertained the notion of a break in the distribution of the species based on the distance of 120 km they thought occurred between the two subclades, the specimen from Eagle Lake in Lassen County and specimen from Nevada County. Had they realized that their specimen from near Quincy in Plumas County
cut that distance about in half, I don't think they would have indicated a break occurred in the distribution of the species.
I get a sense they may have rushed the publication a bit. And it still strikes me odd that none of the reviewers caught that error. I suspect the reviewers were versed in aspects of molecular research and not in natural history.
Richard F. Hoyer
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