Question

Bicoid mRNA is expressed in a gradient in Drosophila embryos. Loss of Bicoid function leads to embryos with two posterior ends. If researchers injected bicoid mRNA into the posterior end of an embryo with no bicoid function, the embryo would most likely develop _.

A normally B with two posterior ends C with two anterior ends D with no anterior–posterior body axis

Answer 1

Injecting bicoid mRNA into the posterior end of an embryo lacking bicoid function would likely lead to the development of two anterior ends (C), as bicoid is responsible for anterior development in Drosophila.

Step-by-step explanation:

• If researchers injected bicoid mRNA into the posterior end of an embryo with no bicoid function, the embryo would most likely develop with two anterior ends.
• The bicoid protein acts as a morphogen that establishes the anterior-posterior axis in Drosophila embryos.
• Normally, bicoid mRNA is localized to the anterior end of the egg, which leads to the gradient formation necessary for the proper development of the head and thorax.
• However, when bicoid mRNA is artificially placed at the posterior end in an embryo lacking functional bicoid, it can lead to the translation of bicoid protein there, possibly mimicking the anterior environment and thus inducing anterior structures in the place of posterior ones.

Answer 2

Option (C) is Right Answer

Step-by-step explanation:

C with two anterior ends

• Bicoid mRNA is actively limited to the anterior of the organic product fly egg during oogenesis along microtubules by the engine protein dynein, and held there through relationship with cortical actin
• Interpretation of bicoid is managed by its 3' UTR and begins after egg deposition
• The posterior region (counting the hindgut) grows and stretches out towards the anterior pole along the dorsal side of the incipient organism
• Segments of the incipient organism become noticeable, making a striped course of action along the anterior-posterior axis