Mutations in EIN3 and EIL1 genes cause strong ethylene insensitivity, whereas mutations of other EIL family members are related to weaker phenotypes, supporting the idea that they are playing an accompanying role during ethylene responses [ 17].
The ade6 3′ UTR was selected because it has been previously reported that nonsense mutations in the ade6 gene cause strong NMD, indicating that the 3′ UTR of this gene is NMD permissive (Mendell et al, 2000).
In order to investigate whether the mutations were causing strong alleles, we examined the level of gene transcription.
It was isolated from a mutagenized seed population and harbours the erecta (er) mutation that causes strong phenotypes such as altered organ shape, compact inflorescence with flowers clustering at the top and round leaves with short petioles and short and blunt siliques [ 21].
In other words, when additional driver mutations caused a strong selective advantage, a mutator phenotype was not necessary for efficient tumorigenesis.
This distribution presents these genes –enriched in various cellular processes [26] – as particularly strong phenotypic modifiers, i.e., their absence revealing a large number of hidden mutations causing particularly strong changes in growth [13].
Several genes involved in the formation of the adult pigment pattern have been identified by mutations causing a strong reduction in number or the complete absence of one or more of the chromatophore types (Johnson et al., 1995; Haffter et al., 1996; Kelsh et al., 1996; Lister et al., 1999; Parichy et al., 1999).
In the loss of function mutants, transcripts of three muscle structural genes (Act 88F, mhc, and Tn I) are increased, and the stronger mutations cause an ∼50% increase in myofibril size.
T315I mutation in BCR ABL causes strong ABL kinase inhibitor resistance in cells.
Perhaps mutations in Stn1 or Ten1 in humans cause stronger phenotypes that are not tolerated.
