Mutations are heritable changes in the genetic material. A mutant phenotype is
a heritable deviant from the standard phenotype, and caused due to mutation. A
mutation is said to be dominant if it expresses in the heterozygous condition. A
mutation is said to be recessive if it requires a homozygous state for its expression.
A recessive mutation on the X chromosome in male is expressed since the Y chromo-some does not carry the corresponding allele, and this is referred to as the hemizygous condition. However, the same recessive mutation on X chromosome needs the homozygous condition in the female for expression.
Symbol : y
Location : 1-0.0
The body is yellow with hair and bristles that are brownish, with yellow tips.
The wings, hairs, and veins are yellow. The larval mouth parts are yellow to
Symbol : e
Location : 3-30.7
The body is black in adults. Larvae show darkened spiracle sheath compared
to wild-type larvae.
Wings and balancers are greatly reduced.
Associated with curly inversion on the left arm (2L) of the second chromosome.
Wings are strongly curved upward and forward. The homozygote is lethal.
White eyes, colorless ocelli, Malphigian tubules and testis.
Brownish-red eyes that darken to sepia and finally to black. The ocelli are wild
Brownish-wine eyes that become purplish with age.