Intron
Introns are portions of genomic DNA which ARE transcribed (and thus present in the primary transcript) but which are later spliced out. They thus are not present in the mature  mRNA. Note that although the 3 flanking region is often  transcribed, it is removed by endonucleolytic  cleavage and not by splicing. It is not an intron.

Inverted. repeat
Two regions of a nucleic acid molecule which have the same nucleotide sequence but in an inverted orientation, such as 5’ GCACTTG... ...CAAGTGC 3 3’ CGTGAAC... ...GTTCACG 5 Because they contain exactly the same message when read in either direction, inverted repeats are said to be palindromes.

In vitro embryo production (IVEP)
The combination of ovum pickup (q.v.), in vitro maturation (q.v.) of ova, and in vitro fertilization (q.v.). A potential means of overcoming the variability between donors in number of ova collected in embryotransfer programmes.

In vitro  transcription; cell free transcription
The specific and accurate synthesis of RNA in the test tube using purified DNA preparations as a template. So called “coupled systems” may be obtained from E. coli which carry out both  mRNA synthesis and its translation into protein. For eukaryotes, separate cell free systems have to be set up to demonstrate the activity of the three functionally distinct RNA polymerase complexes

In vitro translation; cell-free translation
The synthesis of proteins in the test-tube from purified mRNA molecules using cell extracts containing ribosomal sub units, the necessary protein factors, tRNA molecules and aminoacyl tRNA synthetases, ATP, GTP, amino acids and an enzyme system for re-generating the nucleoside triphosphates. Prokaryotic translation systems are usually prepared from E. coli or the thermophilic bacterium, Bacillus stearothermophilus. Eukaryotic systems usually employ rabbit reticulocyte lysates  or wheat germ