Within hours of our expulsion (I use your measurements for time so it will be easier for you to understand) the boss called a meeting of our leaders. When that meeting ended each of the leaders called the rest of us together in groups to explain that the boss had a plan to get us back home soon.
When that plan "failed" the boss organized us into groups according to our primary abilities. After explaining his main goals, he asked us to meet in groups and develop proposals for how our talents could best promote his goals. (I put the word "failed" in quotes because the main portion of the plan succeeded -- it just didn't get us back home. It's all very complicated and too much for me to explain even the little I know here.)
I was assigned to a relatively small group: the bioengineering squad. It is small because knowledge about the physical and chemical details of one's body is far less useful when you are not subject to malfunctions of the body. Before our expulsion this study was viewed as interesting but of limited practicality. Few of us, therefore, put much time into it.
The boss had set as one of his goals the increase of our knowledge in all areas. "Knowledge is power," he said, "and we will need all the power we can muster if we are to succeed." Our squad would work to increase our knowledge of biochemistry.
The boss also wanted to develop an alternative social system on your planet. (Why he picked your planet has something to do with the failure of his original plan. It's all very complicated.) And he wanted to do this in a way that you would think it was all your idea. In short, it was to be a covert operation.
After much discussion we proposed to perform bioengineering experiments on the creatures of your planet, including yourselves. The master had cursed you, taking away your capacity for endless life. Perhaps, we suggested, we could eventually give that back to you if we learned enough about biochemistry.
Very early on, then, we began our work. At that time there were very few of you on the planet, making it easy for us to work undetected. Several of us already understood the mechanics of what you call DNA. We set to work reverse engineering its code so we could use it to do our own biological "programming."
This process took us a couple of hundred years, longer than we had anticipated. And we ran into a most disturbing obstacle. A living cell did things that could not be accounted for on the basis of chemistry or physics; something we were not able to understand. Even the boss had to admit we did not have even the capacity to understand it.
That meant we could not give you our own endless existence. But the boss encouraged us to continue our work. "Learn as much as you can. Who knows what we might be able to do with the knowledge someday?" That's when we began actual physical experimentation.
Because of the barrier imposed by the unexplained phenomenon of the living cell, we could not "cook up" new creatures in the lab. But, through a process you call gene splicing, we could alter existing creatures. Remember that our presence in the fourth dimension allows us to take any form at all in your three dimensions. That way we can achieve molecular manipulation without the fancy machines you are beginning to use.
Our plan, as originally approved, was to generate new forms of creatures by incrementally altering the genes of existing individuals. This would improve our understanding of the DNA code and demonstrate what changes we could and could not make. We would divide into two groups. One group would work on land creatures, the other on sea creatures. I was assigned to the sea group, a most fortuitous chance event, as it turned out.