DNA Identification & Vendors

[cchhcc]

Continuing from another thread, so as to no longer derail it......

Is anyone aware of DNA being used to determine the purity of some of the frequently hybridized species such as labridens? It has been postulated that DNA sequencing could eliminate much of the hybrid talk. Given the endangered status of some species in Media Luna, etc. it would seem appropriate to positively ID some breeding populations.

BUT, what specimen is used as the starting point for that DNA? If the home waters are being aggressively hybridized who determines the "pure" specimen? Could we get DNA material from long preserved specimens?

OR, is the physical description being used to identify the "pure" specimens? In that case, it would seem that DNA identification would be unnecessary at best and of questionable validity at worst.

 

[MTN PIKE]

Are you suggesting Vendors provide DNA?? ~ Good Luck!

 

[cchhcc]

Are you suggesting Vendors provide DNA?? ~ Good Luck!

Haha! No! But some vendors have spouted DNA "this and that" before! And to be fair, you (a vendor) brought up the topic of ending conjecture with "DNA & science" in your thread.

No, I would expect the ACA would likely need to spearhead the effort, or perhaps a well intentioned hobbyist (a.k.a. a not for profit entity) would do the work.

But, if vendors and collectors can't decide what's pure and what's not and who's selling pure and who's not, then don't expect hobbyists to take everything at face value. Some will buy and be happy, and others will require more information. Perhaps one of the latter group would be the one to make the DNA effort.........but if that person were me, I'd make sure to sterilize any fish I gave away so as to prevent an eventual seller from benefiting! Hahaha!

But that topic isn't really important to me. I'm more interested in how the "pure" specimen is identified in the first place.

 

[cchhcc]

OH! I JUST REALIZED I DIDN'T COVER THE "VENDOR" PART OF THE TITLE!

In the vendor part, I meant to address illegal collecting. Basically, I was wondering where people stood on purchasing fish that were illegally collected and smuggled into the country. Say, for instance, someone illegally collects a few fry, puts them in his/her carry-on luggage, and eventually produces saleable fry. Would you feel right about purchasing those fry? I can see several sides to the issue: rule of law, conservation through reproduction, etc........

 

[Modest_Man]

You could in theory get a fin clipping from the preserved type model and then get a "base" DNA sample to compare aquarium strains with although the quality of DNA does degrade over time.

If I was still an undergrad I could run the extraction easily enough. Maybe if I get into grad school next year...

I really enjoy fish and genetics, I'd love to delve into this type of project. A lot of cichlids have had their mitochondrial DNA sequences of the cytochrome b (cyt b) gene mapped. I used to have this full article, let me see if I can dig it up.

H. labridens from Rio Tamasopo and Media Luna have already had DNA analysis in this article. here. You'd just have to get aquarium samples and compare.

Although it states;

The H. labridens sequence analyzed by Roe et al. (1997), does not group with the other H. labridens sequenced (Node 87). Within the Herichthys clade, there appears to be a well-supported split between a group containing H. pantostictus +H. labridens (Media Luna) + H. bartoni +H. labridens (Tamasopo) and another group containing H. minckleyi+ H. cyanoguttatus +H. carpintis +H. tamasopoensis (Node 76). The species H. labridens as it has been interpreted in the past (Artigas-Azas, 1992; Taylor and Miller, 1983) appears to be paraphyletic with respect to H. pantostictus, H. bartoni, and H. steindachneri even when evaluating only the H. labridens sequenced here (Node 77).

I just bring this up because I know this originated in regards to this fish...

 

[cchhcc]

Great post MM!

I noticed the "Academics" misspelled a couple of things, species and gender consistency stuff mostly. I'm sure they're duly embarrassed! Hahaha!

On a serious note, it is interesting to consider the relatively recent date of the studies. The collection of labridens occurred after the hybridization of Media Luna had begun. That speaks to my original point: what is the baseline fish?

Also, when though they reference collection methods it is clear that a large number of fish would be collected (seine and cast nets, electro-fishing) in a random manner. Yet, they make no reference to hybridized specimens. More specifically, they identified species in the field and confirmed them in the laboratory. Depending on the source, hybridized labridens in and around Media Luna are at _____% of the labridens population. However, no reference to hybridized labs is mentioned in the paper, and if one accepts that there is a fair percentage of hybrid labs it could be considered likely that the random sample included one or more hybrids....... See where I'm going with this?

There are some interesting things in the reference list too.

So perhaps a better question/topic is "What percentage of Media Luna labridens are hybrids?"

Or to take it a step further, "What exactly is the difference between natural and unnatural hybridization in the wild?"

(Something tells me those aren't the most exciting topics in the world of cichlids!)

 

[steelayer]

To the question about buy a fish that somone illeagly exported... I would and not think twice about it.

 

[cchhcc]

To the question about buy a fish that somone illeagly exported... I would and not think twice about it.

No, no! You don't get away that easy!

You have to say why!

 

[edburress]

Could we get DNA material from long preserved specimens?

Only if they were preserved in non-denatured ethanol. Most specimens preserved (not specifically for DNA use) are put in formalin at least initially, then transfered to ethanol and in that case couldn't be used.

 

[Nemesis]

OH! I JUST REALIZED I DIDN'T COVER THE "VENDOR" PART OF THE TITLE!

In the vendor part, I meant to address illegal collecting. Basically, I was wondering where people stood on purchasing fish that were illegally collected and smuggled into the country. Say, for instance, someone illegally collects a few fry, puts them in his/her carry-on luggage, and eventually produces saleable fry. Would you feel right about purchasing those fry? I can see several sides to the issue: rule of law, conservation through reproduction, etc........

I believe this question was asked before. And if I'm not mistaken there's a poll for it!