Much of the sequence variation that accounts for
receptor diversity arises
• from alternative splicing
a single gene can give rise to more
than one receptor isoform. After transmlation from
genomic DNA, the mRNA normally contains non-coding regions (introns) that are
excised by mRNA splicing before the message is translated into
protein. Depending on the location of
the splice
sites, splicing can result in insertion or deletion of one or more of the mRNA coding regions,
giving rise to long or short forms of the protein
• from mRNA editing
From mischievous
substitution of one base in the mRNAfor another; different receptors are
produced from the same gene