Monomorphism is a band of DNA that present in all individuals but polymorphism is a marker or band that present in an individual or some individuals but is absent in another individual

Monomorphism is a band of DNA that present in all individuals but polymorphism is a marker or band that present in an individual or some individuals but is absent in another individual

Thanks for your answer.  I still looking for the differences between the monomorph and unique bands

If you have 30 samples on a gel (for example, PCR a gene from 30 plant species), 29 samples have 0.5-kb band, only one sample has 1-kb band, I would consider this 1-kb band a 'unique' band. It is unique to other samples.

The presence of two or more allelic forms in different individuals of  a species call polymorphism. There are different types of polymorphisms.

You may get some information here:

https://www.researchgate.net/publication/273898387_Monomorphic_molecular_markers_are_as_informative_as_polymorphic_molecular_markers

Article Monomorphic molecular markers are as informative as polymorp...

I too looking for the answer of the same question, does anyone explain differences between these three using  arbitrary band size.. 

Lets use the example below to actually differenciate between polymorphic and monomorphic markers either SNPs or what have you.

1. Lets say you have two parents with genotypes XX , YY

2. You have another set of parents with genotypes XX, XX

3. When you screen the above set of parents 1. and 2. with say SNP marker/s, you will notice that the SNP marker will classified 1. XX, YY parents as polymorphic since they have two different alleles (contrasting homozygous alleles) for each parent compared with 2. XX, XX where the parents have the same alleles for each parent.

4. For any successful crosses, you will need parent set 1. XX and YY to get a true or good F1 progeny. Hope this helps.

In brief you have polymorphic when SNPs markers screen parents/lines for two contrasting homozygous set (AA / BB or XX /YY)

You have monomorphic when SNPs markers screen parents/lines for homozyous set for the all the parents (AA/AA or XX/XX or YY/YY)

I agree with Nawroz Abdulrazzak that monomorphic band m is a band of DNA that present in all individuals. on the other side, polymorphic band is a band that present in an individual or some individuals but is absent in one or more.