DNA detector and DNA detection method

Abstract

A method for determining a DNA sequence includes providing a sample which contains first DNA fragments having adenines at an end and labeled by first fluorophores, second DNA fragments having thymines at an end and labeled by second fluorophores, third DNA fragments having cytosines at an end and labeled by third fluorophores, and fourth DNA fragments having guanines at an end and labeled by fourth fluorophores, wherein each of the first to fourth fluorophores is different. The sample is supplied into a capillary and the sample is made to migrate in the capillary. A sheath flow is formed around an end of the capillary where the sample migrates, a light is irradiated into the sheath flow to excite the fluorophores. Fluorescence emitted from the fluorophores is detected and the fluorophores are identified.

What is claimed is:  
     
         1 . A method for determining a DNA sequence comprising the steps of: 
 providing a sample which contains first DNA fragments having adenines at an end and labeled by first fluorophores, second DNA fragments having thymines at an end and labeled by second fluorophores, third DNA fragments having cytosines at an end and labeled by third fluorophores, and fourth DNA fragments having guanines at an end and labeled by fourth fluorophores, and each of said first, second, third and fourth fluorophores being different;    supplying said sample into a capillary;    making said sample migrate in said capillary;    forming a sheath flow around an end of said capillary where said sample migrates;    irradiating a light into said sheath flow to excite said fluorophores;    detecting fluorescence emitted from said fluorophores;    identifying said fluorophores.    
     
     
         2 . A method for determining a DNA sequence according to  claim 1 , wherein said light is irradiated into a vicinity of said end of said capillary.  
     
     
         3 . A method for determining a DNA sequence according to  claim 1 , wherein a plurality of capillaries is provided, and said capillary is one of said plurality of capillaries.  
     
     
         4 . A method for determining a DNA sequence according to  claim 3 , wherein different samples are supplied into each capillary of said plurality of capillaries.  
     
     
         5 . A method for determining a DNA sequence according to  claim 3 , further comprising the step of determining a DNA sequence in each capillary of said plurality of capillaries simultaneously.  
     
     
         6 . A method for determining a DNA sequence according to  claim 1 , wherein the step of providing a sample includes: 
 dividing a sample solution into four parts;    making a polymerase reaction in each part of divided sample solution, and using primers labeled by different fluorophores for each type of terminal base; and    mixing said focus parts of said divided sample solution.    
     
     
         7 . A method for determining a DNA sequence comprising the steps of: 
 providing a sample which contains a plurality of DNA fragments labeled by a plurality of types of fluorophores;    supplying said sample into a capillary;    making said sample migrate in said capillary;    forming a sheath flow around an end of said capillary where said sample migrates;    irradiating a light into said sheath flow to excite said fluorophores;    detecting fluorescence emitted from said fluorophores; and    identifying said fluorophores.