- If an early cleavage stage wild type Drosophila embryo is injected with bicoid mRNA at the posterior pole then
(1) head structures develop at posterior pole, while the same is inhibited at anterior pole
(2) head structures form at both poles
(3) head structures are not formed at posterior pole due to presence of posterior morphogens
(4) duplication of usual posterior structures occursIn Drosophila melanogaster, the maternal effect gene bicoid plays a crucial role in establishing the anterior-posterior axis by localizing its mRNA at the anterior pole of the egg. This localization creates a Bicoid protein gradient that directs head and thorax development.
When bicoid mRNA is experimentally injected into the posterior pole of a wild type early cleavage stage embryo, it creates a novel source of Bicoid protein at the posterior end. This artificially induces a second Bicoid gradient opposite the natural source.
As a consequence, head structures form at both the anterior (normal site) and the posterior (injected site) poles. This phenomenon highlights the morphogen’s dominant influence on anterior structure specification, irrespective of native localization.
Such experiments underscore the fundamental principles of morphogen gradients, positional information, and developmental pattern formation in model organisms.
Therefore, the correct answer to the effect of bicoid mRNA injection into the posterior pole of a wild type Drosophila embryo is:
(2) head structures form at both poles
Answer: (2) head structures form at both poles
16 Comments
Deepika Sheoran
November 10, 2025Head structures from at both poles.
Neelam Sharma
November 11, 2025Head structures from at both poles.
Bhawna Choudhary
November 11, 2025head structures form at both poles
Sonam Saini
November 11, 2025दोनों ध्रुवों पर सिर की संरचनाएँ बनती हैं
Rishu
November 11, 2025head structures form at both poles is the right answer
Kajal
November 12, 2025Head at both the poles
Kirti Agarwal
November 12, 2025Head at both ends
Sonal Nagar
November 12, 2025head structures form at both poles
Priya khandal
November 13, 2025Head at both poles
Neha Yadav
November 14, 2025Head structures form at both poles
Mohd juber Ali
November 14, 2025At anterior side bicoid form head
If we inject bicoid at posterior side head develop at posterior side option 2 is right
Santosh Saini
November 16, 2025Bicoid form head at the anterior side, when we inject bicoid at posterior side then head develop at the posterior side , so option 2nd is correct
Manisha choudhary
November 17, 2025head structures form at both poles
Sakshi Kanwar
November 18, 2025head structures form at both poles
Muskan Yadav
November 21, 2025Answer: (2) head structures form at both poles.
Kavita Choudhary
November 21, 2025Head structure form at both pols