The invention discloses a method for extracting
larva DNA (Deoxyribonucleic Acid) before
metamorphosis of
echinoderm by a freezing method. The method comprises the following steps of: filling
echinoderm larva in a centrifugal tube and preserving in a freezing mode under the condition of -80 DEG C; unfreezing and then adding 15 ul of
cracking solution and 1 ul of 0.3 mg / ml
protease K into the centrifugal tube in 10 minutes;
cracking in a water bath for 3 hours and oscillating and shaking up once every half an hour, wherein the
cracking solution comprises the following components with the following final concentration: 10 mmol / L
Tris-Cl, 50 mmol / L of KCL and 0.5 percent of Tween-20, and the pH is 8.0; heating to 85 DEG C and
processing in water bath for 15 minutes; and directly performing PCR (
Polymerase Chain Reaction) amplification on a sample after cracking to obtain an amplified product, wherein a micro-
satellite amplified PCR
system consists of the following substances: 1 ul of
DNA template, 2.5 ul of 10*buffer, 1.0 ul / each of primer, 2.2 ul of d NTP, 1.5 ul of MgCl2, 0.35 ul of Taq and 15.45 ul of dd H2O, 25 ul in total. The method is easy to operate and does not cause any harm to operators.