Everest Green was determined to go through her four years of college unnoticed by steering clear of any kind of trouble. Law school was her ultimate goal and no one was going to stand in her way, not even the Greek god lookalikes at Bowling Green Un...
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"Pleiotropy," Professor Evans pauses. "It is what we call when some genes affect many different characteristics, not just a single characteristic. As you can see here in the presentation, an example of this is a syndrome called the Marfan syndrome."
"Marfan syndrome results in several symptoms (unusually tall height, thin fingers and toes, lens dislocation, and heart problems). These symptoms don't seem directly related, but as it turns out, they can all be traced back to the mutation of a single gene." Professor Evans explains as he points to the pictures in his presentation.
One of the girls sitting in my row raises her hand and Professor Evans gives her permission to talk. "Professor Evans, isn't pleiotropy the same concept as a polygenic inheritance?"
Professor Evans shakes his head. "I'm afraid you're incorrect Ms. Adams, it was a great question though because that is a common misconception many people have and since it is coming in your final partial exam of the semester, I must explain to you the difference."
"Thank you, Professor." The girl offers a smile.
"As you can see in the next slide, the major difference between the two is that pleiotropy is when one gene affects multiple characteristics (e.g. Marfan syndrome) and polygenic inheritance is when one trait is controlled by multiple genes (e.g. skin pigmentation). Meaning that they are completely different since a gene is a unit of heredity which is transferred from a parent to offspring and a trait is a specific characteristic of an organism." Professor Evans pauses. "Do you have any more doubts about the topic?"
The auditorium stays silent. "Very well, let's move on to the next slide. Ten minutes are remaining of today's lecture and I want to cover one more slide before you leave."
Ev's obsession with having organized notes, unfortunately, has rubbed off on me. The girl color coordinates everything within her subjects. At first, I thought it was something stupid and completely unnecessary but that aged well. I ended up going to the Apple store and I bought myself an iPad. Now, for every one of my subjects, I color coordinate just like her. I will say that it does make things easier when it comes to sitting down to study for my exams, but the thing is that I never saw the day coming when I would be doing the same thing Ev does in class.
"On that same note, there's something that needs to be mentioned. Students, listen carefully, please. This one of the many reasons why many students also fail the exam. Codominance and incomplete dominance are not the same." Professor Evans pauses. "In codominance, neither allele is dominant over the other, so both will be expressed equally in the heterozygote. In incomplete dominance, there is an intermediate heterozygote (such as a pink flower when the parents' phenotypes are red and white)."
The ten minutes passed on by quicker than it felt like. Professor Evans is a great professor, you learn a lot in his lectures but many times the lectures can get monotonous. And it feels like an eternity before it's time to leave. "Remember students, your final partial exam is next week and your essays on your assigned syndrome are due as well. Have a lovely rest of the day and I will see you all in our next lecture."
