You'd have to show me something on that, to be honest. Like the fox experiment or other genetic crosses you can select for a trait it shows up stronger in the first generation.
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. Now to establish a new strain it does take lots of work (I'm using weed here) but lots of shops just replicate the first cross (rather than stabilize to a new strain) over and over to replicate the hybrid vigor. So, if you have two parents with a naturally high speed potential, it's quite possible their offspring would have that trait. Same with singing, intelligence, etc. Of course none of this my research, just reading.