A) gene A is a nuclear gene, while gene B is mitochondrial
B) gene A is highly expressed
C) gene A encodes a transcription factor that controls the expression of one gene
D) gene A controls the expression of many genes
E) gene B encodes a protein that interacts with many different proteins

A) to discover how and whether two proteins interact
B) to locate the chromosomal position of hybridized genes
C) to study the interaction between an enhancer and a promoter
D) to explore a cDNA library to find interacting DNA sequences
E) to study the nature of two hybrid organisms at a time

A) there is a brain- specific allele compared to the other cells in the mouse
B) the skin, liver and heart cells differentiate before the brain and so have different exons
C) the mRNA in the brain is a pseudogene
D) the brain cell chromosome lacks the exon that is present in the other cells of the mouse
E) cells of the brain splice this mRNA differently than other cells in the mouse