Japanese scientists identify genes linked to shell-formation

[Winterson]

Interesting short news story from The Mainichi Daily News:

A team of Japanese scientists has identified almost all of about 30,000 different kinds of genes that form the shell of pearl oysters, a discovery that could shed light on the mystery surrounding the beauty of pearls.

A team of scientists from the University of Tokyo, the Pearl Research Institute of Mikimoto Co., Ltd., and other organizations found 29,682 unique sequences containing novel gene candidates for nacreous and prismatic layer formation, using a device called a "GS FLX 454 system." Some of the genes had already been known, but most of them had not been identified.

The production of the "Akoya" pearl oyster, or pinctada, a genus of pearl oysters, has been decreasing in recent years, but the finding could help select superior species to harvest pearls in high genetic qualities.

On June 23, the research finding was posted on the electronic edition of "PLoS ONE," a publication dedicated to presenting the results of scientific research from any scientific discipline in an open-access environment.

Pearl oysters are raised in many parts of the world, but the pinctada, or the "Akoya" pearl oyster, is said to be particularly beautiful. A pearl is made up of calcium carbonate in minute crystalline form, which has been deposited in concentric layers. The protein trapped between pearl layers is composed of various genes that are believed to control the growth and sparkling of a pearl.

Of about 30,000 kinds of genes identified, 52 of which are involved in the formation of pearl layers, about two thirds of them had been unknown. "We want to uncover the reason why Japan's 'Akoya' pearl oyster can form elaborate pearl layers to produce beautiful sparkles," said Shugo Watanabe, professor at the University of Tokyo.

The original article is at http://mdn.mainichi.jp/mdnnews/news/20110623p2a00m0na017000c.html

 

[Ramona]

Interesting story. Thanks for the link. Here is the article in Plos One:

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0021238

Now the fun starts.

 

[Caitlin]

This is great news! Now they can really put Mendel to work in their breeding programs!

 

[CortezPearls]

This is great news! Now they can really put Mendel to work in their breeding programs!

They have already done it...since the 1960's. And the results were far from being good: they ended up with inbred -genetically weakened- populations and then they had the great idea of chromosome management (poly-ploidism) and caused further damage to the wild-bred pearl oyster populations which some believe led to the massive Akoya pearl oyster mortalities of the 1990's. May God spare us from further "wise use" of genetic techniques.

When Humanity "plays God"...it does a very lousy job. I'd rather have the Japanese producing "lab-grown cultured pearls" than causing further genetic damage on the environment. This -of course- being my personal opinion.

 

[Ramona]

I think genetic engineering of oysters is only doable when using cultured colonies, not wild stock. Even genetic selection should in principle be done only with contained stock to safeguard wild stock. I am surprised this is not monitored. Trying to genetically select oysters is one thing, but manipulating the genome is another and is heavily regulated and not allowed "in the wild", unless a country wants to play it against the rules. My sense from talking to some scientists interested in developmental evolution is that the genetics of oysters is complex and does not lend itself to genetic analysis. Or in others words, in our current funding climate the work would not yield immediate payout and is therefore not fundable and avoided. Expression cloning on the other hand, as done in the report by the Japanese group, will eventually allow to circumvent Mendelian genetics by using a technique called RNA interference. RNA interference can produce an almost complete knockout of any given gene. I bet this is what some of the labs will be doing next. That and overexpress certain gene products to see what effect this has. These approaches are illegal outside a closed and controlled lab environment. They can also be difficult and are very expensive. But knowing about the process does not only have interest to some pearl farmers, but also for the Department of Defense. There is at least one lab in the US that produces nacre in a test tube already.

 

[Caitlin]

They have already done it...since the 1960's. And the results were far from being good: they ended up with inbred -genetically weakened- populations and then they had the great idea of chromosome management (poly-ploidism) and caused further damage to the wild-bred pearl oyster populations which some believe led to the massive Akoya pearl oyster mortalities of the 1990's. May God spare us from further "wise use" of genetic techniques.

When Humanity "plays God"...it does a very lousy job. I'd rather have the Japanese producing "lab-grown cultured pearls" than causing further genetic damage on the environment. This -of course- being my personal opinion.

It sounds like the inbreeders overreached themselves, as is what often happens. Sounds like they took the AKC route to play God. Some akc dogs have an 88% (give or take on that number) inbreeding coefficient. That is daughter to sire, and granddaughter to sire and gt granddaughter to sire to reach that coefficient. (For comparison, first cousins have a 6% inbreeding coefficient). Until scientists give up those Victorian ideas of breeding, there can be no progress. As for using wild oyster populations to do this work in the sea is as dumb as using genetically engineered corn next to regular corn fields. They ought to do work like that in a desert ocean pond, like the ones in which they grow shrimp. We have a bank of them out here in the desert, west of town.

I was not talking about inbreeding at all, but healthiest to healthiest and comparing the genomes. Finding the strongest alleles /combinations for nacre, stuff like that. There is a lot of work before farmers try it commercially. Perhaps study mussels too, because they are often hybridized. Do they hybrid each new generation of mussels or breed hybrids to hybrids? Each way gives a different result. Knowing what members of the f2 have inherited can tell you what is going on.

Are the radiatas 100% the same genetically as the akoyas (within tolerances)? Or can a bit of hybridizing be done to restore specific genes to akoyas lost in the inbreeding? And follow enough generations to know what happened between the varieties......The knowledge from the genome can be used to put oysters with the right genes from the outcross back to the ocean.

I like the work that was done on the human genome, it is revealing a form of history to us. Following the oyster genome the same way will tell us what genes are in the Fiji pearls compared to Tahitians, mostly the same, but there are some rare genes too, that produce slightly different pearls from each other.

But this isn't even my opinion, it is my speculation.

 

[Caitlin]

Yes, Ramona, I am sure you are right. These kinds of pearls can and should be grown in desert salt water circulating ponds and why not always produce them from there? Don't mess with Mother Nature, red tides, typhoons, just make your own little salt water pond. Just like being a real cattle rancher on the free ranges, being an ocean pearl farmer may start getting "barb-wired" in by artificial operations, but they will "never" go away. The feedlot pearls- like the freshwater already are- will spread to sea pearls.......People pay more for free range beef.

And the test tube nacre! It is been reported here before, It has tremendous potential for plastic-like uses - like the side panels of my Saturn- The stuff I saw did not have abalone colors though. Maybe later.

 

[Ramona]

I think you are speculating correctly Caitlin.