Many mutations in the bithorax gene are known, such as postbithorax, contrabithorax and bithoriaxoid. Each mutation has a different effect on development of the reduced wing-like T3 appendage, the haltere. None of these mutations occurs in the coding sequence of bithorax, instead, where are these mutations and how do they effect development?
◦ These mutations alter the slice sites for bithorax and affect the splicing of the bithorax mRNA. Their different effects on development are cause by affects on alternative splicing.
◦ Each mutant alters a different codon within the bitorax gene, which affects the DNA-binding behavior of the bithorax protein.
◦ These mutations each effect silent sites and effect the stability of the bithorax mRNA.
◦ Bithorax is inhibited by zygotic genes from the mother and these mutations affect maternal genes.
◦ These mutations each effect a different enhancer(s) near the bithorax gene and the resulting misexpression of bithorax in each mutant causes patterning defects in the haltere.
Father’s Age and the Number of de novo Mutations
Over time, cells acquire mutations. Two independently acquired mutations in the same cell may be suf
Control of flower formation, as revealed by mutations in Arabidopsis thaliana.
Reversion mutations
E(var) and Su(var) mutations
Mutations in the Beta Globin Gene