prevailing vs dominant

prevailing is not a noun while dominant is a noun.

Word	Noun	Adjective	Verb	Adverb
prevailing	No	Yes	No	No
dominant	Yes	Yes	No	No

As adjectives, prevailing and dominant are synonyms defined as:

Other synonyms of prevailing include predominant, prevalent, rife.

prevailing (noun)	dominant (noun)
	an allele that produces the same phenotype whether its paired allele is identical or different
	(music) the fifth note of the diatonic scale

prevailing (adjective)	dominant (adjective)
most frequent or common	exercising influence or control
	(of genes) producing the same phenotype whether its allele is identical or dissimilar
	most frequent or common