Meanings of independent expression in English

He knew his own mind, and had an independent expression; a very civil, intelligent, and straightforward man.

Owing to the independent expression of opinion in the Diet, Alexander had adjourned that body indefinitely in 1822.

Both mutations confer constitutive copper- independent expression of FRE1 and CTR1.

I did not feel that in Hugh's community there would be much chance of the independent expression of the individualities of his associates!

However, both avian and insect border elements are able to confer position- independent expression as judged from expression of CAT genes in F1 generation fish.