spines on cucumbers

[Nicholas Locke]

Doing some work with my Lebanese cucumber landrace, its is consisted of 2 different varities ,"Beit Alpha" and "Muncher" both fully spineless. I would like to add some more diversity to It. I am growing "Green Finger" very similar to the lebanese types. It is a really nice cucumber but has spines, not many and there seems to be a few almost spineless and some with quite a few.
My Question- are the genes for spines dominate?
I am pretty sure they would be, So if i let "Green finger" cross with my landrace it would be relatively quick and simple to select out any spined plants?
Is there multiple genes responsible for spines ? Is that why there is a sliding scale with spines?