Posted on 01/02/2008 7:36:33 PM PST by blam
Giraffes And Frogs Provide More Evidence Of New Species Hidden In Plain Sight
Genetic subdivision in the giraffe based on microsatellites alleles. (Credit: David M Brown et al., Courtesy BMC Biology)
ScienceDaily (Jan. 2, 2008) — Two new articles provide further evidence that we have hugely underestimated the number of species with which we share our planet. Today sophisticated genetic techniques mean that superficially identical animals previously classed as members of a single species, including the frogs and giraffes in these studies, could in fact come from several distinct 'cryptic' species.
In the Upper Amazon, Kathryn Elmer and Stephen Lougheed working at Queen's University, Kingston, Canada teamed up with José Dávila from Instituto de Investigación en Recursos Cinegéticos, Cuidad Real, Spain to investigate the terrestrial leaflitter frog (Eleutherodactylus ockendeni) at 13 locations across Ecuador.
Looking at the frogs' mitochondrial and nuclear DNA, the researchers found three distinct species, which look very much alike. These species have distinct geographic distributions, but these don't correspond to modern landscape barriers. Coupled with phylogenetic analyses, this suggests they diverged before the Ecuadorean Andes arose, in the Miocene period over 5.3 million years ago.
"Our research coupled with other studies suggests that species richness in the upper Amazon is drastically underestimated by current inventories based on morphospecies," say the authors.
And in Africa, an interdisciplinary team from the University of California, Los Angeles, Omaha's Henry Doorly Zoo, and the Mpala Research Centre in Kenya has found that there may be more to the giraffe than meets the eye, too.
Their analysis of nuclear and mitochondrial DNA shows at least six genealogically distinct lineages of giraffe in Africa, with little evidence of interbreeding between them. Further divisions within these groups mean that in total the researchers have spotted 11 genetically distinct populations.
"Such extreme genetic subdivision within a large vertebrate with high dispersal capabilities is unprecedented and exceeds that of any other large African mammal," says graduate student David Brown, first author of the study. The researchers estimate that the giraffe populations they surveyed have been genetically distinct for between 0.13 and 1.62 million years. The findings have serious implications for giraffe conservation because some among these subgroups have as few as 100 members, making them highly endangered -- if not yet officially recognised -- species.
Journal articles:
Cryptic diversity and deep divergence in an upper Amazonian frog, Eleutherodactylus ockendeni. Kathryn R Elmer, Jose A Davila and Stephen C Lougheed. BMC Evolutionary Biology (in press)
Extensive Population Genetic Structure in the Giraffe. David M Brown, Rick A Brenneman, Klaus-Peter Koepfli, John P Pollinger, Borja Mila, Nicholas J Georgiadis, Edward E Louis Jr, Gregory F Grether, David K Jacobs and Robert K Wayne. BMC Biology (in press) http://www.biomedcentral.com/bmcevolbiol/
Adapted from materials provided by BioMed Central.
Mule is a female horse and male donkey. A hinny is a male horse and female donkey and apparently they are smaller and less easy to get (female donkeys apparently don’t get pregnant by male horses as easily for some reason according to what I read).
A guy who kept his critters where we kept our horses when I was a kid had a jack donkey and kept several shetland pony mares. They had shetland mule babies (very cute).
susie
By the old definition, only one, but by this new definition....many! That’s kind of what got me thinking about it. In fact, I had read somewhere fairly recently that dogs and wolves are really variations of the same species. I expect tho, that it all depends on which expert you talk to. As for me, I am now thoroughly confused.
susie
The problem is, inbreeding can go up through genus and into families.
Dogs and wolves are considered separate species, but can freely inbreed.
Even lions and tigers can inbreed and they're considered much further apart than species.
It seems as though the designations are pretty flexible.
No it is the definition of being to far away to come in to contact in order to interbreed. To be a separate species the two groups would have to be incapable of producing offspring which these groups clearly are able to do.
Maybe. Or maybe the interbreeding is so limited that indeed it makes sense to call them different species, because the distance is simply the cause of speciation or near-speciation.
Actually scientific evidence exists that argues the exact opposite. Salmon have bred in individual streams for millions of years and yet if you place salmon eggs in to a stream different from its native stream those hatchlings when adults will return to the new stream and mate with the salmon native to that stream. Envirowhacos call them distinct species but they are not.
If millions of years of isolated breeding does not cause evolution to occur what does. Most likely catastrophic events of biblical proportions.
Why do I have a this certain feeling that this is gonna cost me money and freedom?
You might be right. Like I said, I'm not even sure why it matters per se whether they are "different species", somewhere in a gray in-between zone, or the same species. As this thread has shown, even the term "species" is a somewhat fuzzy human-invented category. It is of little relevance to anything as far as I can see, outside of creating a tree diagram.
I simply wanted to make the point that a lot of people (whether envirowackos or not) have fallen sway to a kind of "species fetish" way of thinking, according to which larger # of species is always better. I think that's silly, for reasons already stated.
Sorry, I teach this stuff. The definition of species requires a population that can produce fertile offspring in the wild.
You’re missing the “in the wild” part. Dogs are domestic animals.
could be that while related they may not be different species they could be
*clears throat *
Cousins
Meet a frog, who's lived most everywhere,
From Zanzibar to Barclay Square.
But another's only seen the sight.
A frog can see from Brooklyn Heights --
What a crazy pair!
But they're cousins,
Identical cousins all the way.
One pair of matching bookends,
Different as night and day.
Where one adores a minuet,
The Ballet Russes, and crepe suzette,
The other loves to rock and roll,
A hot dog makes her lose control --
What a wild duet!
Still, they're cousins,
Identical cousins and you'll find,
They laugh alike, they walk alike,
At times they even talk alike --
You can lose your mind,
When cousins are two of a kind.
btt
After having slept together for 14,000 years, wolves and dogs are now joined together in scientific matrimony. Quietly, without fanfare in September 1993, wolves and dogs were recognized as the same species. Per the American Society of Mammalogists' Mammal Species of the World, adhering to the Code of the International Commission on Zoological Nomenclature, Canis lupus is the official species of both dogs and wolves. If you have a 'dog', your dog's classification is Canis lupus familiaris, where familiaris is the subspecies of wolf. If you have a 'wolf', your wolf's classification is Canis lupus X, where X is the subspecies of wolf. If you have a 'wolfdog', your wolfdog's classification is Canis lupus familiaris, according to United States Department of Agriculture, Animal and Plant Health Inspection Service, R.L. Rissler, February 21, 1986.
http://www.idir.net/~wolf2dog/annd2.htm
I'm not finding a definition of species that doesn't include some form of: taxonomic group whose members can interbreed
I realize that things change rapidly now that they can actually look at DNA but I also think *scientists* are not above using *science* to further their agendas. I have to say that if a group of giraffes can interbreed with another group, they are so alike that no one realized they were not the same, and there are only 100 of them in existence, they would be a subspecies. But, that probably doesn't get funded... ;)
You mean it would be about money? Tell me it ain’t so...
I knew you’d be shocked!!! ;)
I did some research of my own (ok, I looked on the internet!) several years ago because I got interested in chromosome numbers and interbreeding. I found some really interesting info (did you know that bananas are tetroid—4 sets of chromosomes— and cannot produce viable seeds? They only reproduce from cuttings). But wolves, dogs, coyotes and jackals have the same number of chromosomes, which seems to me indicate the same species. I’m thinking they need to change some of the definitions and maybe invent some new terms (hey someone could probably get a grant for that!)
Oh, and I ran across an article that states that lions and tigers also have the same number of chromosomes, which of course is why they can (but don’t always) produce fertile offspring. You can read it (it’s interesting stuff).
http://en.allexperts.com/q/Genetics-1795/hybrids-sterile.htm#b
susie
I knew bananas were grown from cuttings and last I heard there was some concern about the banana crop and food shortages but that’s all I recall.
Someone on a crevo thread sometime back commented that skeletally, tigers and lions were identical so if you were going by fossil remains, you couldn’t tell the difference. The only reason we know they’re different species is that they are alive today and we can see the surface differences. Which really made me wonder if they are. Seems that slight differences in fur length, patterns of markings, and color shouldn’t be enough to designate species. Look at wolves and dogs again, and even the variety within the domesticated dog varieties.
I really agree. I think the problem is that when everything was being set up we had no clue about chromosomes. That seems to me the be a much better system. Same number of chromosomes, same species.
susie
“Same number of chromosomes, same species.”
Won’t work because chromosomes are not the same as each other. It’s like saying “the same number of coins equals the same amount of money”
Also, two wildly different organisms (say a plant and an animal) can have the same number of chromosomes.
And, just to make things confusing, it is even possible to have differing numbers of chromosomes in one species.
I have to admit I didn’t know that. Can you give me some examples?
susie
Interesting, I did my own research, and you’re exactly right. Of course I used Wikipedia, they had a list of various chromosome counts for different critters and plants, and a number of things have the same number of chromosomes. So, there goes THAT idea out the window! I learn more interesting info on FR!
susie
None whatsoever, unless you're an environmentalist looking to stop a worthwhile project by falsely claiming that a "species" is endangered. These are not separate species, but simply locally adapted "families." You would find far more genetic difference bewtween you and the guy across the street than there is between these animals. (of course you may well be endangered if you don't think politically correct.)
Simple. You taught biology, but this is biopolitics ;o)
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