Question

A mutation seen in Drosophila is found to cause antennae to grow on the abdomen of the flies. What type of mutation is this likely to represent?A mutation seen in Drosophila is found to cause antennae to grow on the abdomen of the flies. What type of mutation is this likely to represent?lethal mutationevolutionary mutationhomeotic mutationsilent mutation

Answer 1

Homeotic mutation

Step-by-step explanation:

This is an example of homeotic mutation. It is hemeotic genes which direct body to develop anatomical/morphological body structures at their appropriate position. But, if there is a mutation in these genes then the body structures are displaced from their actual position and grow at other locations in the body i.e. at an ectopic location.

Since in the given example, antenna which grows at head segment is growing at abdominal segment which is an ectopic location for antenna, this mutation will be termed as homeotic mutation.

Some examples of homeotic genes in drosophila are as under:

Homeotic genes in drosophila are located at chromosome no. 3.

There are two complexes named as Antennapedia complex and Bithorax complex which have several homeotic genes.

Antennapedia complex has 5 homeotic genes named as deformed (Dfd), Labial (lab), proboscipedia (pb), Antennapedia (Antp) and sex combs reduced (Scr) which mainly control the development of appendages in head segment.

Bithorax complex has 3 homeotic genes named as abdominal A (abd-A), Ultrabithorax (Ubx) and Abdominal B (Abd-B) which mainly control the development of appendages in posterior thoracic and abdominal segments.