In Re Fisher
421 F.3d 1365 (Fed. Cir. 2005)
Figure 1: DNA
Table 1: DNA base pairs
DNA
RNA
A-T
A-U
G-C
G-C
DNA, or deoxyribonucleic acid, uses nucleotide molecules of
A (adenine), G (guanine), C (cytosine), and T (thymine) to
make up its structure. As seen in table 1, A molecules pairs
with T molecules and G pairs with C. These sets are called
“base pairs.” RNA, or ribonucleic acid, substitutes U (uracil)
for T (thymine).
Figure 1 depicts molecular DNA with the linked base pairs
and the hydrogen bonds between them.
Figure 2: Protein Synthesis
Protein synthesis occurs through the process of transcription and
translation. (Figure 2) The first step is through replication of DNA.
DNA is then transcribed into messenger RNA or mRNA. After, mRNA
can then translate into a protein using a ribosome, or it can produce
complementary DNA, cDNA, through reverse transcription.
EST’s are short nucleotide sequences that are created by sequencing
either ends of a strand of cDNA.
5’
cDNA
3’
ATTAACGCTATCCATTGGATTGCAATGCCGTTAT
TAATTGC
CGGCAATA
3’
EST
5’
3’
EST
5’
EST strands can attach to the original DNA to help with sequencing the genome, can attach to mRNA to
determine if the mRNA is present and the amount, and can identify when mutations of the DNA occur
called “polymorphisms.”
Fischer essentially wanted to patent small strands of sequenced DNA which were created from the
maize plant DNA. These small EST strands would be the maize DNA verbatim. While EST’s do not
naturally occur, the sequence of the EST does exist within the DNA of the maize plant.