Nucleic acid ladders

Abstract

The present invention provides nucleic acid compositions or ladders which may be used as standards for estimating the size (in base pairs) and or mass of nucleic acid molecules of unknown size and/or mass. The invention also relates to methods for producing such compositions or ladders, ladders or compositions produced by such methods, and to methods for estimating the size and/or mass of nucleic acid molecules by comparison to these nucleic acid sizing ladders.

1 . A composition or ladder comprising a mixture of nucleic acid fragments of different lengths wherein the relative mass of each fragment is substantially equivalent. 
     
     
         2 . The composition or ladder according to  claim 1 , wherein said different length fragments produce bands after gel electrophoresis, said bands having substantially equal intensity. 
     
     
         3 . A composition or ladder comprising a mixture of nucleic acid fragments of different sizes, wherein the differently sized fragments are capable of producing bands after gel electrophoresis and staining, said bands having substantially equal intensity. 
     
     
         4 . The composition or ladder according to  claim 1 , wherein said nucleic acid in DNA. 
     
     
         5 - 37 . (canceled) 
     
     
         38 . A method for sizing one or more nucleic acid molecules of unknown length, said method comprising:
 separating according to size the fragments of the composition or ladder according to  claim 1  with said nucleic acid molecules; and   determining the size of said nucleic acid molecules.   
     
     
         39 . A kit comprising fragments of  claim 1 . 
     
     
         40 . The kit according to  claim 39 , wherein said fragments are mixed in a single container. 
     
     
         41 . (canceled) 
     
     
         42 . (canceled)