A better way of preparing DNA ladder is by PCR amplification using primers designed for getting amplification of the desired sizes from any selected template.

Try Restriction digestion in plasmid having different restriction sites. 

A better way of preparing DNA ladder is by PCR amplification using primers designed for getting amplification of the desired sizes from any selected template.

http://agris.fao.org/agris-search/search.do;jsessionid=78C90F2A94A60C3FC96B4CDBF357A517?request_locale=es&recordID=US201300836192&sourceQuery=&query=&sortField=&sortOrder=&agrovocString=&advQuery=¢erString=&enableField=

I agree with Dr.Singh

I agree with Dr.Singh

To make high-molecular weight standards I use a linearized plasmid and partially religate it at a high concentration to get mainly concatamers.

However I have never used it with 100kb plasmids/cosmids. I guess it should also work!?

Best regards,

Christian

Hi dear

this link can help you

https://www.neb.com/~/media/Catalog/All-Products/2EE823104BE849D3AB2F2E7A2E08779A/Datacar