1. A method of quantifying relative abundance of mRNA in a biological sample, said method comprising the steps of: (a) isolating an mRNA population from the biological sample; (b) identifying gene transcripts by a sequence-specific method, which method comprises (i) making cDNA copies of the mRNA; and (ii) isolating a population of the cDNA copies and producing therefrom a first cDNA library, wherein a selected set of random primers was used in the generation of the first cDNA library; (c) determining a number of gene transcripts in the mRNA population that encode the same gene product; (d) processing in a programmed computer the number of gene transcripts that encode the same gene product to calculate a relative abundance of the transcripts within the population of gene transcripts, wherein said relative abundance is calculated by tabulating the number of gene transcripts that encode the same gene product to generate an abundance number and dividing the abundance number by the total number of gene transcripts in the mRNA population to obtain a calculated relative abundance number for each identified gene transcript; and (e) processing the calculated relative abundance of each gene transcript to generate a gene transcript image of the biological sample; wherein the gene transcript image provides a calculated relative abundance that is quantified for each gene transcript.