The human eye disease retinitis pigmentosa is caused by a lossof function mutation (rp) in the gene PRPF31. The disease isexpressed when combined with wildtype allele 1 (rp+1) in aheterozygote, but not expressed when combined with wildtype allele2 (rp+2) in a heterozygote. When comparing the number PRPF31 mRNAtranscripts in the eyes of rp/rp+1 and rp/rp+2 individuals,researchers have found a higher number of functional PRPF31 mRNAsin the eyes of rp/rp+2 individuals. This is an example of ______caused by haploinsufficiency or haplo-sufficiency________ when isrp occurs in the same genotype as rp+2.
