Genes

How many genes have an impact on building muscle mass and whether it can be something that prevents further development?

No one knows exactly. The human genome is still quite poorly understood. Chances are, unless you're already a very high level athlete, you're not yet at a point where your genetics are limiting you. 

definitely the gene of miostatin. look of the web for the bulls that have super muscles. with genetic engineering they locked the production of the gene for miostatin control and result is more and more muscles mass.natural? no , is recombined genome.

at low level is better talk about the speed to transcription and expression for unit of time. this is quite relevant talking about strength and muscle gain. what really do very expensive steroids is increase the rate of production of hormones.

Ask a strong guy how they got there and they'll tell you it's through effort, ask him why he isn't as strong as the next guy and he'll tell you it's genetics. 

 

Equivalent effort amongst different people won't produce equivalent results, and the strongest guys probably have a genetic advantage. In a competitive setting, genetics and body type are really important (training and how much you put in is of course fundamental as well). But for the rest of us, I wouldn't get caught up on it.

 

Natural talent is an interesting subject, but as Josh said, the influence of genetics on performance is really poorly understood. When you add in the environmental effects on genetics and how they express themselves (epigenetics) things get even more complicated.

 

Coach posted an interesting video recently about natural talent in sports: https://www.gymnasticbodies.com/forum/topic/16116-are-athletes-really-getting-faster-better-stronger/#entry155862

 

The speaker is also the author of a book I've been wanting to read for a while: http://thesportsgene.com/

Maybe you'll find some better answers there.