Here's what rhymes with polymorphism.

Consider these alternatives

nucleotide / side mutation / operation alleles / varies haplotypes / types allele / very phenotype / might mutations / relations heterogeneity / deity genomic / economic unsaturation / operation recombination / information microsatellite / right genotyping / writing variability / stability nucleotides / types haplotype / might directionality / personality multivariate / late dimorphism / dwarfism genotype / might morphological / logical parallelism / given chromosome / home genetic / magnetic homology / quality translocation / relation