How are varieties of yeast developed?

I’m looking for information on how the various commercial strains of yeast are developed from scratch.

What is involved in the process of developing a yeast from scratch? (i.e. From the time it is captured (or can you cross breed yeast?) to being able to sell it.)

Also, there must be a limited number of yeast strains worldwide (not sure if all have been discovered), but they must be cataloged somewhere. (i.e. The yeast with this DNA sequence is the German Lager variety, etc…)

Searching the Internet has only brought me confusion on this subject, if someone could explain it plainly that’d be a real help.

Not sure how many yeasts are actually engineered from scratch - many of the strains available through Wyyeast or White Labs were collected from bottles or from breweries or other “direct” sources. This site has good info on sources:

Thank you Shadetree. That is an excellent resource.

Now if it could be taken one step further and examine where/how the breweries obtained their yeast?

It is interesting to note how the re-labeling/branding/marketing gets in the way of the origins of the yeast. I’d be curious to know if these companies have to license or pay royalties for the yeast?

I’d guess a (generic, not so terrific) answer to my question would be that way back when, some yeast was captured by the breweries in specific parts of the world and simply propagated forward from there. Which is mildy interesting, but these folks certainly didn’t have the laboratories of today.

How were these breweries and yeast propagations set on the right track and to what date do the varieties of modern yeasts go back to? Have the yeasts evolved over time to produce cleaner/better beers, or is the modern laboratory responsible for that?

Copyright laws and such don’t apply very well in the food world. You can own a brand name but try"owning" in the same way a recipe. I figure this is why many companies don’t state what there recipes are for foods or beer/wines. Even something like a copywritten cookbook cannot lay claim (i.e you cant make that without permission) to the recipes in the book. There is no legal reason you cannot collect yeast from any commercially produced beer, reculture it, and using exactly the same recipe make that very same beer. You cannot sell it under the brand name it came from but you could freely sell it under a new name.