A method of amplifying genomic DNA of a cell, comprising: (a) providing a reaction mixture, wherein the reaction mixture comprises the genomic DNA, a first type of primer, a second type of primer, a mixture of nucleotide monomers, and a nucleic acid polymerase, wherein the first type of primer comprises, in a 5' to 3' orientation, a common sequence and a variable sequence, and the second type of primer comprises the common sequence but not the variable sequence, wherein the common sequence consists of three or two types of bases selected from the group consisting of four types of bases: G, A, C and T, provided that the common sequence does not comprise G and C at the same time, wherein the common sequence is selected such that the common sequence does not substantially bind to genomic DNA to cause amplification, wherein the variable sequence is selected from the group consisting of nGGG, nTTT, mTNTNG, wherein N refers to any nucleotide that can pair with a naturally occurring nucleic acid, n is a positive integer selected from 3-17, m is a positive integer selected from 3-15; (b) placing the reaction mixture in a first thermal cycle program such that the variable sequence of the first type of primer can pair with the genomic DNA and amplify the genomic DNA to obtain a genomic amplification product, wherein the genomic amplification product comprises the common sequence at its 5' end and comprises complementary sequence of the common sequence at its 3' end; (c) placing the reaction mixture obtained from step (b) in a second thermal cycle program, such that the common sequence of the second type of primer can pair with 3' end of the genomic amplification product and amplify the genomic amplification product to obtain an expanded genomic amplification product, wherein the reaction mixture is provided prior to the step (b) and the step (c). (a) providing a reaction mixture, wherein the reaction mixture comprises the genomic DNA, a first type of primer, a second type of primer, a mixture of nucleotide monomers, and a nucleic acid polymerase, wherein the first type of primer comprises, in a 5' to 3' orientation, a common sequence and a variable sequence, and the second type of primer comprises the common sequence but not the variable sequence, wherein the common sequence consists of three or two types of bases selected from the group consisting of four types of bases: G, A, C and T, provided that the common sequence does not comprise G and C at the same time, wherein the common sequence is selected such that the common sequence does not substantially bind to genomic DNA to cause amplification, wherein the variable sequence is selected from the group consisting of nGGG, nTTT, mTNTNG, wherein N refers to any nucleotide that can pair with a naturally occurring nucleic acid, n is a positive integer selected from 3-17, m is a positive integer selected from 3-15; wherein the first type of primer comprises, in a 5' to 3' orientation, a common sequence and a variable sequence, and the second type of primer comprises the common sequence but not the variable sequence, wherein the common sequence consists of three or two types of bases selected from the group consisting of four types of bases: G, A, C and T, provided that the common sequence does not comprise G and C at the same time, wherein the common sequence is selected such that the common sequence does not substantially bind to genomic DNA to cause amplification, wherein the variable sequence is selected from the group consisting of nGGG, nTTT, mTNTNG, wherein N refers to any nucleotide that can pair with a naturally occurring nucleic acid, n is a positive integer selected from 3-17, m is a positive integer selected from 3-15; (b) placing the reaction mixture in a first thermal cycle program such that the variable sequence of the first type of primer can pair with the genomic DNA and amplify the genomic DNA to obtain a genomic amplification product, wherein the genomic amplification product comprises the common sequence at its 5' end and comprises complementary sequence of the common sequence at its 3' end; (c) placing the reaction mixture obtained from step (b) in a second thermal cycle program, such that the common sequence of the second type of primer can pair with 3' end of the genomic amplification product and amplify the genomic amplification product to obtain an expanded genomic amplification product, wherein the reaction mixture is provided prior to the step (b) and the step (c).