Dear,
Yes …yes…yes ( how many times do you want me to say it hahahaha….).
See the point of taking our education to the level of Ph.D. is only one that is- interest , it is and was always independent of your master’s .
So , both of us know one thing for sure that the principles of molecular biology are universal … whether you apply it to plants , giant animals or microorganisms.
Same goes with the subject changing phenomena and you’s i must tell you is not a very big change you are just going from skills to application part , you get acquired with all the techniques in biotechnology and then if you want to apply it to the field of zoology…then whoooooohooooo( sound weird na! i know ^.^) go for it my dear , the field of zoology is waiting for you and yes ! after doing biotechnology it will be much easier for you to juggle with any field … just like love marriage , one must do Ph.D. in the arena of their interest.
PS- One of my senior in my laboratory had done her post graduation from microbiology and Ph.D. in plant stem cell biology now she is doing post doc in plant biology from USA.