what is the difference between di-allelic,mono-allelic and poly-allelic?

Question

anonymous · Answer

I think it refers to qualities that are depend to
one allele to show the phenotype=mono
tow alleles(they can be co-dominant,incomplete dominant,lethal alleles...)
more than 2 alleles,like your length,or ABO blood group

blues · Answer

Alleles are variants of genes. The prefix - mono for one, di for two and poly for many - refer to how many variants each particular gene has.

anonymous · Answer

what is the example of mono-allelic?

blues · Answer

Actually, almost all genes are mono-allelic.

Take, for example, the gene which codes for KIT (a receptor tyrosine kinase). There is only one kind of KIT and only one allele which codes for it. The same could be said of any essential protein which is the same in all members of any species (not just humans). 

A very good question, thanks for asking it!